Emscripten compilation with 2d trackables

First version build with 2d trackables (jpeg)

--   C/C++:
--     Built as dynamic libs?:      NO
--     C++ Compiler:                /Users/thorstenbux/repos/emsdk/fastcomp/emscripten/em++  (ver 6.0.1)
--     C++ flags (Release):         -O3 -s ASSERTIONS=0 --llvm-lto 1 --memory-init-file 0 -s INVOKE_RUN=0 -s NO_EXIT_RUNTIME=1   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-implicit-fallthrough -fdiagnostics-show-option -pthread -Qunused-arguments -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -DNDEBUG -O3  -DNDEBUG
--     C++ flags (Debug):           -O3 -s ASSERTIONS=0 --llvm-lto 1 --memory-init-file 0 -s INVOKE_RUN=0 -s NO_EXIT_RUNTIME=1   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-implicit-fallthrough -fdiagnostics-show-option -pthread -Qunused-arguments -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -g  -DDEBUG -D_DEBUG
--     C Compiler:                  /Users/thorstenbux/repos/emsdk/fastcomp/emscripten/emcc
--     C flags (Release):           -O3 -s ASSERTIONS=0 --llvm-lto 1 --memory-init-file 0 -s INVOKE_RUN=0 -s NO_EXIT_RUNTIME=1   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-implicit-fallthrough -fdiagnostics-show-option -pthread -Qunused-arguments -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -DNDEBUG -O3  -DNDEBUG
--     C flags (Debug):             -O3 -s ASSERTIONS=0 --llvm-lto 1 --memory-init-file 0 -s INVOKE_RUN=0 -s NO_EXIT_RUNTIME=1   -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -Wno-implicit-fallthrough -fdiagnostics-show-option -pthread -Qunused-arguments -fomit-frame-pointer -ffunction-sections -fdata-sections  -fvisibility=hidden -fvisibility-inlines-hidden -g  -DDEBUG -D_DEBUG
--     Linker flags (Release):      -O2 
--     Linker flags (Debug):        
--     ccache:                      NO
--     Precompiled headers:         NO
--     Extra dependencies:
--     3rdparty dependencies:       zlib libjpeg libwebp libpng IlmImf
-- 
--   OpenCV modules:
--     To be built:                 calib3d core features2d flann highgui imgcodecs imgproc java_bindings_generator python_bindings_generator video videoio
--     Disabled:                    dnn js ml objdetect photo shape stitching superres videostab world
--     Disabled by dependency:      -
--     Unavailable:                 cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev java python2 python3 ts viz
--     Applications:                -
--     Documentation:               NO
--     Non-free algorithms:         NO
-- 
--   GUI: 
--     GTK+:                        NO
-- 
--   Media I/O: 
--     ZLib:                        build (ver 1.2.11)
--     JPEG:                        build (ver 90)
--     WEBP:                        build (ver encoder: 0x020e)
--     PNG:                         build (ver 1.6.34)
--     OpenEXR:                     build (ver 1.7.1)
-- 
--   Video I/O:
--     DC1394:                      NO
--     FFMPEG:                      NO
--       avcodec:                   NO
--       avformat:                  NO
--       avutil:                    NO
--       swscale:                   NO
--       avresample:                NO
--     GStreamer:                   NO
--     libv4l/libv4l2:              NO
--     v4l/v4l2:                    NO
--     gPhoto2:                     NO
-- 
--   Parallel framework:            none
-- 
--   Trace:                         YES (built-in)
-- 
--   Other third-party libraries:
--     Lapack:                      NO
--     Custom HAL:                  NO
--     Protobuf:                    build (3.5.1)
-- 
--   NVIDIA CUDA:                   NO
-- 
--   OpenCL:                        YES (no extra features)
--     Include path:                /Users/thorstenbux/repos/webarkit/artoolkitX_em_2d/Source/depends/emscripten/opencv-3.4.1/3rdparty/include/opencl/1.2
--     Link libraries:              Dynamic load
-- 
--   Python (for build):            /usr/local/bin/python2.7
-- 
--   Matlab:                        NO
-- 
--   Install to:                    /Users/thorstenbux/repos/webarkit/artoolkitX_em_2d/Source/depends/emscripten/build_opencv-em/install