More work on CS projects and platform depends.
Route to MSDN for mtcore docs. Nice!
Nixed cruft.
Put all codex metadata in .codex instead of scattering it about.

Though it is nice to think that you can delete a directory and its codex
metadata goes away as well, but it's both a) annoying to scatter crap all over
the file system, and b) some projects have the same "root" (DLL projects), and
c) some project roots are on non-writable file systems (like when we're
grinding MonoTouch standard libraries or the Java source from java.home).

I'll eventually add some sort of project garbage collector that blows away
projects and metadata for projects whose root disappers and we'll call it good.
Make sure we don't forget the last compunit.
Report path when initting database.
Added support for DLL projects, other related revampery.

We use monodis to extract type info from a DLL and then keep that in our
database. We can't navigate to said symbols, but we can show documentation for
them and handle adding includes for them (not yet implemented).