markup cleanup and white space consistency

* removed an extra </span> in the layouts
* adde a space befor the Contact sentence in the footer
* removed some trailing spaces
* since most of the sass was done with tabs converted the rest of the files to tabs
* removed mixed cases where tabs and spaces were used
* moved the mixin in helpers to the mixins partial
* added new lines to the bottom of the sass files so diffing is easier
Optimized Images

* reduced pallet to 16 for the pngs
* ran all through ImageOptim
Merge pull request #5 from pierceray/cleanup

markup cleanup and white space consistency