Rename .gitignore file.
Updated .gitignore to include backup files.
Added Atmel ATmegaxx4 generic variant.  Currently contains boards for only '644PA and '1284P.
Added Wiring board variants.
Also contains specific variant for the Wiring S Play Shield (which has a non-standard pin layout compared to atmegaxx4-generic).
Added Rogue Robotics boards.
Contains a board variant which is non-generic, but can be used as a template for others to maintain compatibility with ATmega328PA variants.
Merge pull request #3 from bhagman/master

Added Wiring and Rogue Robotics.