Consistent sections order & headers in contrib docs
Summarize contrib apps on docs index
- Remove contrib app overview
- Decided against using an English name for the apps, as they are not standardized
  and the description seems like enough.
Standardize contrib app installation docs
Syntax highlighting for all code snippets in contrib docs
Update nav bar info in httptester docs
Better docs for BaseHandler.test
This was mentioned in #265 and #220 but those issues were closed before the change was made.
Changes in response to comments from @dpoirier
1. Autonumbering was not working probably because of extra paragraphs in list
2. Messaging should be numbered to be like httptester and locations
Merge pull request #311 from rapidsms/291/docs-cleanup

refs #291 - Docs cleanup