8.19pre

ccminer-819prerelease-cuda91-x64.zip
ccminer-819prerelease-cuda8-x64.zip

fix x17 for Linux builds without NVML
trying to fix crashes under Linux
change exit behaviour
show default intensity when not using the -i option
add gpu number to the cuda error messages

Known Problems:
With some algos Linux users will get validation errors. In this case please use the option --no-cpu-verify.
On some systems ccminer will crash when there are connection problems.