Update instruction comments in application.js
Pass size of 60px to gravatar function from navbar. Since it won't be larger than that, no point loading a larger 200px image and then shrinking it. 60px already takes into consideration retina displays. The actual size of avatar is 30px.
Refactor gravatar function
Remove mongoose reference
Update Contributing section
Update jsdoc strings
Merge remote-tracking branch 'origin/master'

* origin/master:
  Added Express tutorial link
Fixed minor bug in the flash example in README.md

Minor bug in the req.flash Data Usage Controller example. String passed instead of an object wrapped string.
Update README.md
Merge pull request #62 from blister/master

Fixed minor bug in the flash example in README.md
Added OS icons to Prerequisites
Add CSRF input to Account Delete form.
Merge remote-tracking branch 'origin/master'

* origin/master:
  Added OS icons to Prerequisites
  Update README.md
  Fixed minor bug in the flash example in README.md
Removed form-control and form-group classes from CSRF inputs. Placed them at the top right after form block for consistency
merge from upstream