Fix null ref when writing assembly to runtime
Fixes https://github.com/aspnet/KRuntime/issues/910

@Chengtian @muratg
Servicing work in progress
Servicing file format update

Changing key=value delimiter to =
Long path redux
- Rely on FilesChanged to trigger new compilations
- Removed most of the directory watching code from roslyn compilations

#961
Fixed regression on mono

- Use HOME instead of ProgramFiles
- Removed tracing for replacement attempts
#974
Made some changes to how DTH sees wrapped projects
- Fix up the dependencies list when returning wrapped csproj and
assemblies.
- Changed how unresolved dependencies were implemented. This allows
a specific IDependencyProvider to say a dependency is resolved, but mark
it as unresolved so that fallback does not happen.
- Remove special logic from the UnresolvedDependencyProvider and made it
a first class property on LibraryDescription.
- Mark projects as unresolved if they do not have a compatible target framework
#945
Preserve original project.json paths in DTH
- Added new WrappedProjectPath to the ProjectReference message. This
allows us to preserve all information so that editors can watch the
relevant project.json and wrapped project.
Tweaked unresolved project logic
- Mark projects as unresolved only if frameworks are specified
and none of them match.
Fixing the casing issue with word Nuget -> NuGet

kpm pack command line help contains the word Nuget. Fixing this to NuGet per Eilon's CR feedback.
Updating to release NuGet.config
Updating to dev NuGet.config
Add a solution that we test "kpm wrap" against
Add functional tests for "kpm wrap" on Windows
Add diagnostics info for "kpm wrap" functional tests
Turn off KRE_TRACE when verifying "kpm wrap" test output
Remove a broken "kpm wrap" test case
Only use the contract on platforms that support them
Replace string interpolation with string.Format()
Merge branch 'release' into dev