[coffeescript mode] Stop strangely fetching options from conf.mode

That's what the parser configuration object is for. Also,
I am unsure how this was supposed to even work.

Issue #2996
Make ctrl-double/triple-click work again

Issue #2997
[javascript mode] Be more conservative about detecting fat arrow syntax

So that => in a string or comment doesn't trigger weird indentation.

Closes #2993