V2.0 backwards compat fixes

**Status**: *Review*
**Reviewers**: @noahadams  @johnboxall 
**JIRA**: ???
**Linked PRs**: #244 
  
## Changes
- Adds a bunch of checks so that the tests that use Jazzcat.js in 1.1 don't break
- Backports an issue with Jazzcat for Firefox
  
## How to test-drive this PR
- Run the tests by running `node tests/server.js &` and navigating to http://127.0.0.1:1337/tests/index.html
  
## TODO
- Jazzcat in 2.0 is not designed to work with Adaptive Templating. This needs to work for both 1.1 and adaptive.js.