Just load the jasmine methods directly from jasmine env

This should resolve #58.

Basically instead of creating a proxy to all the Jasmine methods, I just directly set all the methods on `env` to the `window` object.

I've manually tested this on my project for Jasmine `2.0.4` and `2.1.2` and it ran through all the tests fine.

Let me know if there are any concerns with this method.
Sorry, `ddescribe` it doesn't have anymore. Instead it has been renamed to `fdescribe` and `fit` methods.

The `xit` and `xdescribe` methods have remained the same.