Use modern Travis badge format
Remove note about official repo location

The point has been made by now.
It also makes for a useless README excerpt (on GitHub mobile, etc.).
Move CI database setup to before_script
Remove unused development dependencies
Fix param handling in the dump_yaml task
Fix the name of the dump_yaml task in readme
Merge pull request #89 from grk/fix-dump-task

Fix the dump_yaml task
Remove note about Rails 3.2 compatibility
Use HTTPS GitHub URL