Language Selection

Fixes #144. This adds a language selection dropdown to the footer which allows the user to change their language which will result in changing the site content. This will also make it clear that #160 is not an issue.
This is triggering for me locally in both Firefox and Chromuim
```
[01/Aug/2014 08:08:27] "POST /i18n/setlang/ HTTP/1.1" 302 0
[01/Aug/2014 08:08:27] "GET / HTTP/1.1" 200 20436
[01/Aug/2014 08:08:30] "POST /i18n/setlang/ HTTP/1.1" 302 0
[01/Aug/2014 08:08:30] "GET / HTTP/1.1" 200 19923
[01/Aug/2014 08:08:30] "GET /static/js/site.js HTTP/1.1" 304 0
[01/Aug/2014 08:08:30] "GET /static/css/sandstone/sandstone-resp.less HTTP/1.1" 304 0
[01/Aug/2014 08:08:34] "POST /i18n/setlang/ HTTP/1.1" 302 0
[01/Aug/2014 08:08:34] "GET / HTTP/1.1" 200 20436
[01/Aug/2014 08:08:39] "POST /i18n/setlang/ HTTP/1.1" 302 0
[01/Aug/2014 08:08:39] "GET / HTTP/1.1" 200 19923
[01/Aug/2014 08:08:39] "GET /static/js/site.js HTTP/1.1" 304 0
[01/Aug/2014 08:08:39] "GET /static/css/sandstone/sandstone-resp.less HTTP/1.1" 304 0
[01/Aug/2014 08:08:42] "POST /i18n/setlang/ HTTP/1.1" 302 0
[01/Aug/2014 08:08:42] "GET / HTTP/1.1" 200 20436
[01/Aug/2014 08:08:50] "POST /i18n/setlang/ HTTP/1.1" 302 0
[01/Aug/2014 08:08:51] "GET / HTTP/1.1" 200 19923
[01/Aug/2014 08:08:51] "GET /static/js/site.js HTTP/1.1" 304 0
[01/Aug/2014 08:08:51] "GET /static/css/sandstone/sandstone-resp.less HTTP/1.1" 304 0
```