Rename dotfiles to prevent them being ignored as files for the generator

Fixes #40

Apparently dotfiles and others can be interpreted by the generator itself if they are not renamed. (See evidence in Yeoman's own [generator-generator](https://github.com/yeoman/generator-generator/blob/master/app/index.js#L146-L152)). 

This solution uses a dotfile copy solution similar to the one given here:
http://stackoverflow.com/q/24844951/1601953

The renaming scheme is a bit clunky, but works by removing the prepended underscore from each common filename.