Version bumps for devDependencies

Version bumps for devDependencies
* grunt 0.4.1 > 0.4.5
* grunt-contrib-concat ~0.1.2 > ~0.5.0
* grunt-contrib-cssmin~0.6.0 > ~0.10.0
* grunt-contrib-uglify ~0.1.1 > ~0.6.0
* grunt-contrib-jshint ~0.1.1 > ~0.10.0
* grunt-contrib-nodeunit: ~0.1.2 > ~0.4.1
* grunt-contrib-watch: ~0.2.0 > ~0.6.1
* grunt-contrib-clean: ~0.5.0 > ~0.6.0
* grunt-contrib-copy: `0.4.1 > ~0.7.0
* grunt-contrib-compress: ~0.5.2 > ~0.12.0

Includes adding .sass-cache directory to .gitignore
Includes adding .editorconfig from core svn