Remove unused function
Remove targetVendor field from Target
Don't export platformString
Move archShortString to Android module and don't export it
Fix overlapping pattern match warning
Remove toolChainFromEnvironment stub function
Move Target and related definitions to separate module
Add TargetOS type
Remove version field from Platform

The version is now passed to the toolchain creation function on each platform. This also allows determining the version in the Action monad.
Expose Target constructor and remove label accessors
Fix compiler warnings
Output contents stderr before stdout
Remove unused/trivial utility functions
Remove Host OS type and use Target OS instead
Return default toolchain build flags in Action monad
Re-introduce Host operating system type
Remove ?=> utility function
Put universalBinary in Action monad instead of Rules
Refactor OSX functions for getting sdk root and platform versions
Remove deprecated modules Configuration and SourceTree