Added SBT plugins

Squashed commit of the following:

commit 267e2bfcd6e34fa75e6756a7c80267f89907b0ad
Author: Anish Athalye <aathalye@me.com>
Date:   Fri Jul 19 07:51:16 2013 -0400

    Added SBT IDEA plugin

commit caac0d75937bcbfc51fdc4079725960297caa451
Author: Anish Athalye <aathalye@me.com>
Date:   Thu Jul 18 21:55:18 2013 -0400

    Added SBT Scalastyle plugin

commit 5b2a81f199bd002460fd22efb0fa6e5528394e7d
Author: Anish Athalye <aathalye@me.com>
Date:   Thu Jul 18 21:38:42 2013 -0400

    Added .gitignore for SBT

commit e98efeaca4a17d8a70508ad78116280f06f47bcb
Author: Anish Athalye <aathalye@me.com>
Date:   Thu Jul 18 21:38:31 2013 -0400

    Added SBT Scalariform plugin

commit 9ae9d20dd5d20b5599ac49dbfb24f96c93d18b93
Author: Anish Athalye <aathalye@me.com>
Date:   Thu Jul 18 20:08:38 2013 -0400

    Added SBT eclipse plugin