Move gulp-jasmine to jasmine-npm

Since minijasminenode2 doesn't seem to be supported anymore, and I
needed the beforeAll added to Jasmine 2.1, this is a first shot at
moving gulp-jasmine to the official implementation of jasmine for node.
I haven't tried to add custom reporters, and the default reporter
doesn't support isVerbose and includeStackTrace, so I deactivated these
options, but the rest looks functional enough. Haven't implemented a
gulp module before, so let me know if I can do anything better.
Good question. I don't think it is, since jasmine returns a constructor anyway. I'll have a look Monday. But that reminds me that I think there's a bug in the cache emptying logic below that, since it only resets the cache for 2 levels. I remember when I first used gulp-jasmine that I had this bug where the code wasn't reloaded, and I think that's the reason. What I do in my gulp file is remove everything from the cache that doesn't contain "node_modules". Should I look more into this?