Add podspec.

Summary:
This will allow people to add Material components to their app using Cocoapods.

Example `Podfile`:

    platform :ios, '8.0'
    pod 'material-components-ios/Typography'
    pod 'material-components-ios/ShadowLayer'

Reviewers: randallli, ajsecord, #mux

Reviewed By: ajsecord, #mux

Projects: #material_typography, #mux, #material_components_ios

Differential Revision: http://mux-oss-phabricator.appspot.com/D34

material-components-ios.podspec

@@ -0,0 +1,74 @@
+Pod::Spec.new do |s|
+  s.name         = "material-components-ios"
+  s.version      = "0.1.0"
+  s.authors      = { 'Apple platform engineering at Google' => '[email protected]' }
+  s.summary      = "A collection of stand-alone production-ready UI libraries focused on design details."
+  s.homepage     = "https://github.com/google/material-components-ios"
+  s.license      = 'Apache 2.0'
+  s.source       = { :git => "https://github.com/google/material-components-ios.git", :tag => s.version.to_s }
+  s.platform     = :ios, '7.0'
+  s.requires_arc = true
+
+  # # Subspec explanation
+  #
+  # ## Required properties
+  #
+  # public_header_files  => Exposes our public headers for use in an app target.
+  # source_files         => Must include all source required to successfully build the component.
+  # header_mappings_dir  => Must be 'ComponentName/src/*'. Flattens the headers into one directory.
+  #
+  # ## Optional properties
+  #
+  # private_header_files => This should point to your component's Private/ directory if you have any
+  #                         private headers.
+  # resource_bundles     => If your component has a bundle, add a dictionary mapping from the bundle
+  #                         name to the bundle path.
+  #
+  # # Template subspec
+  #
+  # Find-and-replace for 'ComponentName' is your friend once you copy-paste this :)
+  #
+  #  s.subspec 'ComponentName' do |ss|
+  #    ss.public_header_files = 'ComponentName/src/*.h'
+  #    ss.source_files = 'ComponentName/src/*.{h,m}', 'ComponentName/src/Private/*.{h,m}'
+  #    ss.header_mappings_dir = 'ComponentName/src/*'
+  #
+  #    # Only if you have private headers
+  #    ss.private_header_files = 'ComponentName/src/Private/*.h'
+  #
+  #    # Only if you have a resource bundle
+  #    s.resource_bundles = {
+  #      'MaterialComponentName' => ['ComponentName/MaterialComponentName.bundle/*']
+  #    }
+  #  end
+  #
+
+  s.subspec 'ScrollViewDelegateMultiplexer' do |ss|
+    ss.public_header_files = 'ScrollViewDelegateMultiplexer/src/*.h'
+    ss.source_files = 'ScrollViewDelegateMultiplexer/src/*.{h,m}'
+    ss.header_mappings_dir = 'ScrollViewDelegateMultiplexer/src/*'
+  end
+
+  s.subspec 'ShadowLayer' do |ss|
+    ss.public_header_files = 'ShadowLayer/src/*.h'
+    ss.source_files = 'ShadowLayer/src/*.{h,m}'
+    ss.header_mappings_dir = 'ShadowLayer/src/*'
+  end
+
+  s.subspec 'SpritedAnimationView' do |ss|
+    ss.public_header_files = 'SpritedAnimationView/src/*.h'
+    ss.source_files = 'SpritedAnimationView/src/*.{h,m}'
+    ss.header_mappings_dir = 'SpritedAnimationView/src/*'
+  end
+
+  s.subspec 'Typography' do |ss|
+    ss.public_header_files = 'Typography/src/*.h'
+    ss.source_files = 'Typography/src/*.{h,m}', 'Typography/src/Private/*.{h,m}'
+    ss.header_mappings_dir = 'Typography/src/*'
+
+    ss.private_header_files = 'Typography/src/Private/*.h'
+    s.resource_bundles = {
+      'MaterialTypography' => ['Typography/src/MaterialTypography.bundle/*']
+    }
+  end
+end