Add refills hero, cards to welcome, purple colors

Specifically, I create a hero component and a cards component, borrowed
from refills. The hero component is pasted directly inside; cards
component is in the refills/ directory

Colors have been changed to a cool shade of purple, and variables in
_variables.scss have been updated accordingly.

Finally, the new hero image (to be replaced, perhaps) has been added to
assets, and the welcome controller has been updated accordingly
Add devise views

Because I'll be modifying these later, and because I need to
differentiate between the different layouts of my app
Add devise layout, remove application #main div

...to include the #main wrapper in the devise views

And also change the main application layout to remove the superfluous
double #main
Add main div to other view pages

To compensate for #main div being removed from the application layout

TODO: I may have missed some views - I'll fix those when I encounter
them
Improved header, added footer, better flashes

Made general improvements to header and footer layout of the site in
the _layout partial. Also, flashes are now centered and good to go.
Import normalize_rails and refills

Whoops, forgot to add these changes.
Add welcome/index styles
Reduce box shadow on games