Refactor app from RC4 to Angular 2 Final

[vorugantia]

In this PR I fully refactored the app to work with the latest Angular update (hopefully stable for the future). I built the app from a fresh start but didn't have to change most of the content itself - I mainly just copied over code. However, here are the major changes implemented in this app:

• Updated dependencies in package.json
• Subcomponents and other dependencies for each component (declarations, providers) are now defined in modules and not in the component itself. To read more about modules and the NgModule decorator, read more from their docs, here. Along with the main AppModule that is bootstrapped to the app itself on startup (just like how AppComponent used to be in RC4), I created two subdivisions, MapViewModule and CatViewModule, to help organize dependencies in the scope of just the MapView and CatView pages. Then I created a SharedModule for any components that need to be shared between both the MapView and CatView pages (like the button to switch views).
• New routing interface as a part of Angular 2 Final update. Routing has been made more modular - each file contains the RouterModule decorator. Just like the modules mentioned above, the RouterModule can have subdivisions to organize your app. Aside from the main AppRoutingModule, I implemented a MapViewRoutingModule and a CatViewRoutingModule, and each one takes care of the child routes for that view.
• Little forms interface tweak for the CatSearchComponent, both for Angular 2 modules and for the ng2-bootstrap modules.
• Moved around some config files and removed any unnecessary ones, since webpack will now bundle the app differently. I did this by following the migration guides to see which files were important.

The code blocks themselves are mostly exactly the same as before - there is no need to review them all in detail. I would mainly just look over how I implemented the modules. After this PR is merged, we should be ready to deploy the app to the website.

[cdeil]

npm start and the webpage works locally for me. This is great!

I don't know why this branch has commits from me and merge commits: https://github.com/gammapy/gamma-sky/pull/57/commits OK to merge as-is this time. For future PRs: please start from master, don't name your feature branch "master", and use rebase instead of merge if you have to sync with the master branch because there have been changes in the meantime.

My main concern here is that ng e2e tests are failing: https://travis-ci.org/gammapy/gamma-sky/builds/171816620#L3851 As I've said in https://github.com/gammapy/gamma-sky/issues/34#issuecomment-238103319 it would be very good to have some automated tests that show that the webpage is basically working (so that we don't do manual re-testing for every future pull request).

If you don't want to fix this here, merging as-is is also OK with me. We still have #34 as a reminder that there should be some working tests. I'll assign #34 to the 0.2 version milestone now.

Otherwise: I'm very short on time and don't know Angular very well, so I'd be OK to merge the code without review.

One thing you could check is whether the commonly used commands developers need are still valid, now that we use Angular 2.1? https://github.com/gammapy/gamma-sky/wiki/Developer-documentation#javascript

[vorugantia]

Don't have time now to fix/figure out the tests. We're still getting an error with travis-ci, even after I commented out the spec.ts files, but I haven't looked at the log yet. I'll just merge this PR for now.