Add .gitattributes and normalize line endings

This is the preferred solution for line ending issues. The repository on the server will have LF and each client will be in the native line ending. We get this one big commit as everything is normalized but going forward we shouldn't get any walls of pink.

See this [Blog Post](http://www.hanselman.com/blog/YoureJustAnotherCarriageReturnLineFeedInTheWall.aspx) for more details

Fixes issue #319