JSON responses, templates & Capistrano integration

This release includes breaking changes.

Added

• Add Capistrano 2 & 3 integration (#13)
• Add support for defining Cog Templates (#3)
• Add support for returning JSON to Cog (#3)
• Arguments can also be accessed by their names (#53)

Changed

• Bundle-related configuration is now grouped together (#41)

Fixed

• Cog arguments are now ordered properly (8a550)