Refactored the assembly loaders
- Simplified IAssemblyLoader.Load
- Added more types to the service provider so that
  the RoslynAssemblyLoader can be type activated with the service provider
- Made IFileWatcher assembly neutral
- Renamed LazyRoslynAssemblyLoader to ProjectAssemblyLoader
Split project export resolution into the core
- Made ProjectExportProvider which is an uber ILibraryExportProvider that
  returns an ILibraryExport for the entire project based on the
  specified target framework.
- Added IMetadataRawReference which reflects assembly metadata as a byte[]
- Made EmbeddedMetadataReference implement IMetadataRawReference
- Simplified roslyn compiler logic by using the new ProjectExportProvider as
  part of the compilation process.
- Improve tracing in ProjectExportProvider
- Pass the ILibraryExportProvider to GetProjectExport
Fixed active target framework for compilation
- ProjectExportProvider now returns the effectiveTargetFramework in
  an out parameter.
- The RoslynCompiler uses this as the effective target framework for
  compilation.
fix build.sh on XDG_DATA_HOME and copy nuget.exe

The correct way to verify the variable is using -z.
To copy a file on bash you need to specify the filename also, not the
folder only.
Added execute permission to build.sh.
fix build.sh to use wget -O instead of -o
Move k build to kpm build
- Removed old unused scripts
- Removed --native option from build
Made kpm work on core clr.
- ifdeffed out RemoteWalkProvider
- Shimmed ProtectedData, ConsoleColor and AsReadOnly()
Added build back to Microsoft.Framework.Project to ease the transition
Make the project manager in the produced kre work.
Fixed the LocalizedResourceManager
Enclose paths in scripts with double quotes
Updated based on CR comments.
Enable CrossGen tests