Bring back default `rake ib` and `rake ib:open` tasks

No need to create an instance of IB::RakeTask unless you need to modify the IB::Project instance.

0.7.0 Alloy's refactors

Eloy Duran (@alloy) has gone to great pains to get this gem updated and working with the latest RubyMotion features. Sweet!

v0.4.2

Version 0.4.2