Python 3 compat:

1) use types.FunctionType if new.function is not available
2) use open() instead of file()
Merged Ty Sarna's Python 3 compatibility work
Attribute passthrough for lighten()ed app objects (e.g WebOb Response)
On Py3, instancemethod only takes 2 arguments.
Typo fix
Py3.2 source compatibility: only a little ugly.  (Tests not included!)
Alpha version of @lite.wraps() for middleware decorators
Clarify decorator positioning concerns
Doc tweaks for new @lite.wraps decorator
More doc tweaks
Tweak @lite.wraps() to allow wrapping non-WSGI functions
Classes can now be bindable w/new __wsgi_bind__ method; minor Py3 fixes
Minor doc fixes
Bump version to release snapshot
Fix bitbucket link
Added tag 0.5a3 for changeset 439fc3161620
Fix packaging issues w/0.5a3
Added tag 0.5a3-1 for changeset bcb41f724d02