travis: simplification

I played with docker to be able to run the .travis.yml file locally and had to make some changes.

```console
$ docker run greut/invenio:test /bin/bash -c \
                "runtests git://github.com/inveniosoftware/invenio.git#pu"
```

Travis seems to do some magic there and I don't want to replicate that.

**changes**
* Installing the npm dependencies globally, less configuration.
* Forcing non interactive versions of apt-get and make-ssl-cert.
* Fixing uglifyjs to uglify-js, different projects.
* Ignoring stuff from bower.io.
* Can be used by the docker container greut/invenio:test to test a particular branch just like travis would.

**having fun with it :dancers:**
To make it even cooler, grab [two audio files](https://archive.org/details/opensource_audio) and get notified when it fails miserably.
```console
$ wget https://tgstation13.googlecode.com/svn-history/r1404/trunk/sound/misc/sadtrombone.ogg
$ wget https://raw.githubusercontent.com/straup/inception-horn/master/inception.ogg
$ docker ... && mplayer inception.ogg || mplayer sadtrombone.ogg
```