Fine tune compilation changes
- Remove source files update as precompilation
will be handled differently.
- Only emit the required target framework for assemblies.
- Requesting assemblies no longer compiles, the logic was changed to:
 - On the very first request for compilation, mark the request for assemblies.
 - When that assembly is outdated, trigger a recompile for that particular
   target framework. The idea is that you will be running the same project
   over and over again.
- Swallow IO exceptions as they are usually connections dropping (which
is expected)