Clean up ErrorReporter

Now takes python 'self', better error checking, other small cleanups.
Better error handling in getExecutablePath
Place debug builds in build/, release in bin/
Pull submodule forward
Add some more application tests

Fixes #77, at least for the time being.
Clean up CMakeLists a bit
Fix incorrect type for pointer

Necessary for 64-bit compatible implementation.
Refine some warnings with VST host callback
Compulsively order declarations in function head
Pull submodule forward