Various fixes and improvements

[cs]

1. pulled from damireh: added indices to timeline_events migration
2. pulled from rohit: Remove extra whitespace from migration template
3. .gititnore all *.rbc files (generated by rubinius)
4. require active_record instead of activerecord in order to support 3.1 series or rails (maybe 3.0 series as well)
5. fix test. for some reason moch has_entry method is undefined on my system. replace has_entry with "full" expectations to fix the issue (same technique as in other tests). note: has_entry is supposed to be defined in mocha.
6. multitenancy support: add belongs_to :account to timeline event incl. support for passing :account to the fires macro. tests are up to date as well.

hope you like it! thanks!