Add example Gearfile and gearspec files.
Update specification for Gear/Gearbox.
Add stub commands.
Modify command CLI a bit to make it easier.

Some subcommands are moved now into the main CLI class.
Refactor configuration and environment.
Add 'Gearfile' template for initialization.
Require a minimum of Ruby 1.9.3 to run.

Many people have yet to make the leap to 2.0.0 and there really is no
reason why this needs to be required to actually run.
Add basic minitest runner and Guardfile.