[Ide] The assembly references in the type system are now lazy.
Getting references is a slow operation now. Therefore it makes sense
to postpone that as long as possible.
[Ide] ProjectWrappers are now valid when they're loaded & references
are connected.
It's no longer needed to have all dependent wrappers references
connected anymore.
[Ide] Simplified the type system loading.
It's no longer needed to deeply load the referenced assemblies.
Furthermore I simplified the loading state - it's now much more less
error prone.
[UnitTests] Track API changes.
[Core] Cache assembly references returned by msbuild