Fix responsive display for tablet and mobile in course about page
Refactor style of shopping cart list and receipt
New style for billing error page
Fix shopping cart list
Change h2 color in XModules
Update new forum button style
Update xblock h2 style
Change text of buy course button
Fix shopping cart button in nav
Fix translation in receipt page
Start adding less and grunt tasks
Start adding style for course about page
Update course about page style
Update course about page
Add mixin to create rounded tables
Update global style and course about page
Start changing dashboard style

Also fix a few overrides.
Add mixins for buttons (edx-btn and edx-btn-hover)

Apply to current buttons.
Split mixins into multiple files
Contextualize global elements