[WIP]v0.3.0

Updates for release of v0.3.0

### Changes
* Added default neat settings to the `_settings.scss` file
* Removed `pxtoem()` function in favor of Bourbon `em()` function
* Removed `pxtoper()` function in favor of Sass `percentage()` function
* Removed inuit arrows in favor of Bourbon arrows
* Removed inuit box-sizing in favor of Neat's box-sizing
* Changed clearfix class to a silent placeholder
* Changed unstyled-list class to a silent placeholder


* Removed default theme files (from /modules and /layout)
* Added viewport meta info
* Updated imagemin task to overwrite images rather than duplicate them

### Review

@germanny 
@ericrasch 
@jameswlane 

### Notes

**These changes are not backward compatible and will break existing projects.** Be sure to read the list of changes and understand what they do.