3rd-party-merge: add basic version matching

The original design was that people could only install the latest version
of packages and that's it.  Requests are now coming in to support older
SLOTs (like getting python-2.7).  That means we have to make the merger
more intelligent and support extended atoms like "dev-lang/python:2.7".

TEST=merging with python:2.7 works now

Change-Id: I6085adf87a37a601e2ebace9894ac5e558f448a4
1 file changed
tree: f1f522db1fb18f148591d2a2d6f08e03f18fa054
  1. etc/
  2. usr/
  3. .gitignore
  5. setup_board
  6. wrapper.py