disqus work
* fix #309
sanize disqus input
* uses the textilze filter to sanitize blog post title
* I'm worried you may lose older comments since this actually changes the title
** wasn't able to load comments locally at all (even without changing title) so I suspect disqus is storing comments on the url when no identifier is set
Should fix #300:
1. Modifying preprocessor so that every bootcamp entry in _config.yml always has a URL field.
2. Modifying other code to always rely on this.
Post about Cambridge R bootcamp
Merge pull request #310 from acabunoc/redesign

disqus work
Typos and other corrections
Blog post about URI bootcamp
Merge pull request #313 from gvwilson/blog-uri-bootcamp

Blog post about URI bootcamp
Fixing typo. Should be ready to publish now
Merge pull request #312 from apawlik/postCambridgeR

Post about Cambridge R bootcamp
Fixing up blog post about Cambridge R bootcamp
Merge pull request #314 from gvwilson/blog-cambridge-r-bootcamp

Fixing up blog post about Cambridge R bootcamp
Fixing capitalization in title
Merge pull request #311 from gvwilson/fixing-bootcamp-urls

Should fix #300: bad bootcamp URLs in calendar.
Navbar work
* mostly the collapsed the bar, make less awkward
* some link colour changes
navbar & links
* input from @r-gaia-cs
* links on hover: darker & underline
* move search bar to bottom on collapse
Fixing Mozilla Science Lab logo in "About Us"

The svg logo of Mozilla Science Lab use some special font that can
be unavailable in some machines and for that reason we should use
a png version of it.

Similar problem had been report in #250 and fix in #254 for home
page and now we fix it to "About Us".
Merge pull request #316 from r-gaia-cs/fix-logo-about-us

Fixing Mozilla Science Lab logo in "About Us"
Change header case for @r-gaia-cs
Merge pull request #315 from acabunoc/master

Navbar - make smaller screens a bit prettier