Added new CLI option skip-save and mvc-framework as well as ember support

See issue #19
This is my first proper code-submition so if there is anything I should change, just tell me. I know the commits aren't squashed (because I found a little bug), but since I think it needs some feedback as well as some fixing of tests I thought I would do a pull request.

I hope the update readme.md explains how to use the new commands. To get the old default behaviour, use:
yo karma --skip-save

Furthermore, I thought I would add bower.json and package.json file generation, so beginners can immediately see what dependencies are needed. The bower.json won't be created completely clean all the time (it has some empty lines sometimes and commas are on the next line), but couldn't really figure out a better way.

Some further notes: As mentioned before the tests need some fixing, maybe someone could help me with that, since I don't have too much experience. To be precise, somehow adding this.app.options['mvcFramework'] = 'ember'; doesn't do anything and I don't know how to test that certain files shouldn't exist.
With the 'mvc-framework' argument it shouldn't be too hard to add more framework support and also changing this code to the new karma 0.9/0.10 conf shouldn't be too much effort.
What are your thoughts?

PS: Also just saw I forgot to add the ember-mocha-adapter to the bower.json. Will do soon.