Add WarnHandler to automatically capture warnings, and re-emits them at the end of the session. Recods now remember the originating test
Fix warn formatting to display WARNING source cause
WarnHandler is just another part of logging
Revert "WarnHandler is just another part of logging"

This reverts commit f2bc24b99c6d61cf252e1b0e0e6fc9ce02cd5f51.
Warning now printed (and tested) via reporter
Merge branch 'dev' of git://github.com/omergertel/slash into omerg

Conflicts:
	tox.ini
Separate session log handlers to a session sub-object
Silence warnings as a part of the result reporter tests
Remove unnecessary import