Jasmine Externs are out of Date

I've found that many Closure externs are out of date for Jasmine. Specifically, I see:

* Many custom matcher types are missing, including:
* `CustomMatcherFactories`
* `MatchersUtil`
* `CustomEqualityTester`
* `CustomMatcher`
* Jasmine's pretty print utility is missing (`jasmine.pp()`)
* Most matcher functions (`toBe()`, `toEqual()`, etc.) accept an optional string to use as an error message if the expectation fails. This is also missing.
* Likely others...

Without these types, custom matchers are basically impossible. Would be great to see these types updated.

See: https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/jasmine/index.d.ts