Bootstrap V3 Upgrade

Upgraded Bootstrap version primarily to allow for advanced grid manipulation particularly on smaller devices. 

Notes about the upgrade:
- Box-Sizing is now Globally declared as Border Box
- Images are no longer responsive by default
  - Have added responsive functionality by default in style.css
- Instead of just one grid, there are now three, col, col-md, and col-lg
  - Replaced all instances of 'span' with col-lg.