Return comment and position information from parser

Return comment info from parser, which will be used later for
pretty printing a parsed Blueprint file.  Also add more position
information to the AST.

Change-Id: I3cf0ba8ea4ba5b931d032098ae5fdc350806ed98
5 files changed
tree: 6512ce2151128afbf08da93ea1114b5bad29efc9
  1. blueprint/
  2. Blueprints
  3. bootstrap.bash
  4. build.ninja.in