Implement basic DidAttach and DidLaunch for DynamicLoaderWindowsDYLD.

Summary:
This commit implements basic DidAttach and DidLaunch for the windows
DynamicLoader plugin which allow us to load shared libraries from the
inferior.

At the moment, I'm unsure how we're going to gather the load address of
the main module over gdb protocol so I always use an offset of 0, which
works well for processes we create ourselves (no randomization). I will
address this point later on.

Reviewers: clayborg, zturner

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D12245

llvm-svn: 245725