R1:fcaeb2aeb6d9

Be more strict with JSHint.

Summary: Add a bunch of extra checks to be performed by `jshint`. For documentation, see http://jshint.com/docs/options/.

Test Plan:
Ran `jshint --config support/jshint/jshintconfig webroot/rsrc/js/`. There were a bunch of existing violations, but some of these are legitimate and probably require attention.

```lang=json
{
"bitwise": true, // 0 violations
"curly": true, // 0 violations
"immed": true, // 1 violation
"indent": 2, // 0 violations
"latedef": true, // 10…