Arbitrarily split up to make git bisect easier.
These unnecessary #include's were found by combining an automated tool (which
determined likely candidates) and some brain power (which decided whether
the #include is also semantically superfluous).
My favorite #include:
#include "Applications/Piano/Music.h" // You can't have too much music in life!
This parser will be used by the C++ langauge server to provide better
auto-complete (& maybe also other things in the future).
It is designed to be error tolerant, and keeps track of the position
spans of the AST nodes, which should be useful later for incremental
parsing.
