Merge remote-tracking branch 'upstream/master' into sql

Conflicts:
	Rakefile
	motion_model.gemspec
bundle update bubble-wrap to 1.3.0
Ensure the database is reset when running SQL specs
Add specs for the SQL adapter

One new method introduced: It is now possible to
call `select` directly on a class in the same way
`where` or `find` are called.

These tests are not exhaustive and they reveal
some incomplete areas. Most notably around
Transactions.