Updates to php and javascript

- added simple and base php form email functions
- common js functions
  — a[rel=external]
  — .js-hide .hide()
  — $.ajax -> to functions.php to email form

- base.scss
  — removed @imports
- mixins.scss
  — border-radius()
  — added -o prefix to mixins
- added
  — modules.scss
  — ui-elements.scss
README.md

Added more instructions on installation and usage.