Resolves #2688 - w/ filter
Add ambiguity to jslint tooltip in the case of a stop notice
Don't count the stop notice.

If there is a stop notice then JSLINT.errors looks like:
[..., an error, an error, stop notice, null]. This means 
there are JSLint.errors less nulls subtract one many 
actual errors to count.
Merge pull request #2690 from kjgorman/kjgorman/jslint-non-null-counting

Resolves #2688 - Incorrect JSLINT status bar count