Fixed SASS Compiling

-Moved SASS files to their own directory (out of css/)
-Updated application.js to compile the main SASS file and generate the
single output CSS
-Added a watch for any changes made to SASS files and trigger the SASS
compile when changes are made.
-Compiled SASS outputs to both app/ and generated/ directories
-Removed watch for SASS files from jekyll build so jekyll doesn’t have
to build every time SASS files change.
-Updated head.html to reference new main.css file which is not minified
(we’ll need to change this to minified after dev is close to complete,
easier to debug for now)
Iterating on mock-up for /media page