Allow task loading from Rakefile for gems (plugin installation already auto-detects). Add skip_on_db_migrate option as well for people that don't want it.

fix the dependencies so it doesn't fail when multiple version of Rails is installed, reported by kuroda

* update gem with newgem
Add my plugin addons:
* annotate geometrical columns
* annotate object daddy
* annotate spec models
Annotates in the end by default.