Fixed cross browser compatibility with flexbox & added timesince

Fixed cross browser compatibility with flexbox & added timesince to date.

- Added browser vendor-prefixes for flexbox through sass mixins. (https://github.com/mastastealth/sass-flex-mixin)
- Removed old & unused creative commons code
- Removed some classes that were automatically added through Ghost.
- Moved all styling from style.scss
Added time to posts in index.

Closes #7
- Added time with timeSince.js to index
changed some static values to use sass-variables

changed some static values to use sass-variables
Fixed Sass-variables

Changed all colors to use sass-variables and renamed color sass-variables

- All colors now have a descriptive name, eg $blue for blue color and $dark-grey for a dark grey.
- Color is specified with a variable at all places (except the Github code formatting for Highlight.js which won't be touched)
Merge pull request #16 from reedyn/browser-compatability

Browser compatability and minor cleanup