Lint: Tighten .jshintrc options and enforce them.

Lint: Tighten .jshintrc options and enforce them.

Re-ordered .jshintrc to be alphabetical once again (like on
jshint.com/docs/) and by section (predef, restriction,
toleration, environment, legacy).

Enforce eqeqeq:true, and hard-code camelcase:false since we
have a few underscore ones.

"delete x" problem:
* "delete x" never passes jshint, we should use window.x instead.
* "delete window.x" doesn't work in IE6-8 (throws exception)
* "delete x" only works for "x = 1", not for "window.x".
* Only solution I see: use IE @cc comments for the IE version
  of the test.
* See also http://jsfiddle.net/8X6cS/6/
  IE6: supportDeleteProperty = false, jscriptVersion = 5.6
  IE7: supportDeleteProperty = false, jscriptVersion = 5.7
  IE8: supportDeleteProperty = false, jscriptVersion = 5.8
  IE9: supportDeleteProperty = true, jscriptVersion = 9
  IE10: supportDeleteProperty = true, jscriptVersion = 10

Follows-up dbd005333d23dc1b248a3b6d17f32ab2b2396c66