Merge branch 'master' into dev
Fixed mutable to_s bug.

Signed-off-by: Andy Triggs <andy.triggs@gmail.com>
Merge pull request #1 from LaunchThing/c00e5feb80b6df7c29a629632ae662c9cec7cde7

I fixed a bug where subsequent requests to to_s yielded different results.
Merge branch 'dev' of github.com:ammar/regexp_parser into dev
Fixed another instance of the mutable to_s bug (Thanks to andyt)
Cleaned up token classes
Added mrun's run files to .gitignore
Cleaned up the scanner code and improved EOF handling especially within sequences. Adding tests.
Fixed a bug in subset parsing where all members after a subset ended up in the subset. Minor cleanup in expression.rb.