Support timeout mocks on ie8

See http://www.adequatelygood.com/Replacing-setTimeout-Globally.html
for description of the problems and solutions.
Jasmine's `boot.js` [already has](https://github.com/pivotal/jasmine/blob/15f3d0e9d7841e46676ce991c95e00abc49b2eb2/lib/jasmine-core/boot/boot.js#L89-L95) this hack.

Fix #41