Install task

Simply run `make install` to install all dependencies and build the project:

- Bundler & Gem dependencies (here: Sass)
- node modules
- bower components

It also launches a gulp build and mocha tests.

![screenshot 2014-11-06 17 10 50](https://cloud.githubusercontent.com/assets/85783/4940146/f3a3810a-65d7-11e4-8a48-8ed30959c7d6.png)

I'd prefer this as test will get more complex (jshint + server + client)
```
install:
    // everything except test
test:
  // test
setup: install test
     @echo "\nIf everything is green, you're good to go!\nType 'make run' and open http://localhost:5050"
```