fix firefox window.getInterface leak and access iframe via window[iframeIndex] leak
fix: mocha.globals([...]) make tests run very slow
fix: use mocha.globals([...]) make tests run very slow
Merge branch 'improve-global-leaks'

* improve-global-leaks:
  fix: use mocha.globals([...]) make tests run very slow
  fix: mocha.globals([...]) make tests run very slow
  fix firefox window.getInterface leak and access iframe via window[iframeIndex] leak

Conflicts:
	lib/runner.js
	mocha.js