Implement robot injector mechanism

Closes #7

See merge request !2

We now use the function defined in `lib/controller` to load the resources to
inject into the client.

The order of the "modules" to be loaded is defined as follow:
- controller
- lib
- robot

Each module corresponds to a specific folder in the `client` folder.

This module allow to load all the files that must be injected into the client.

We define three modules to be injected in the client:
- controller: in charge of exposing the hubl.in functions as a unified API
- lib: containing various libraries to be used by the robot
- robot: containing the behavior of the robot itself

Currently these modules only contain the base skeleton.

Instead of a single controller file, `runner.run` now takes a list of source
files that will be injected in the passed order.

- `robotClientController.js` moved to `client/controller/controller.js`
- `controller` renamed to `robotController`
- changed some `var` to `const`
- updated path to controller in `app.js`

Update package.json

See merge request !1

`package.json` contained a lot of missing or incorrect info. Fixes this.