Add well-known JS variables to be ignored

There are some well known global variables that cause JSHint warnings. We should
add them to the list of ignored variables.

* ignore jquery variables
* ignore angular variables
* ignore jasmine variables
* sort the JSHint options
* combine ignored varibales from both configs
* move active_support test dependency into fast_spec_helper

https://trello.com/c/1kUi8THW
Rescue malformed JSON config

Since we cannot parse the repo configuration, return an empty hash, as if the
was no configuration at all.