100% working high-DPI/Retina images inside pages.

We now output:

  <img src="<thumb>" srcset="<thumb 2x big> 2x, <thumb 1.5x big> 1.5"/>

and mimic the srcset attribute behavior, which hasn't even been implemented by any browsers yet, using a JS polyfill.

I hacked sorl-thumbnail to produce the correct alternative-resolution thumbnails.  There's a related pull request @ sorl-thumbnail, so hopefully it will be accepted.  I also fixed up this "srcset-polyfill" JS that mimics srcset behavior - wasn't quite working for me as-is on my iPhone.
+ sorl-thumbnail custom in setup.py
Bigger img + retina on info page.
Basic responsive image scaling.

Doesn't swap out img src yet.
Allow zooming.
Merge branch 'master' into responsive_philip
Merge branch 'master' into responsive_philip
Tons of responsive work, inc. nav at top.

+ jquery on every page.
+ nav.html template changes that customized nav.html will have to fix on upgrade
Bringing CHANGELOG up to date w/ dev.localwiki.org
simple editor on small screens. aw yeah.
Fixing up save/cancel buttons
Better comment box for save
Some edit area cleanup.
Hide address bar on iOS, Android.
Some missing ckeditor files.
navbar fixes. almost perfect
Fixes #407.
Fixes #412. I think.
Fixes #402.
Fixes #403. Not perfect but good enough.

God this is cool.