Feature/setup protractor for testing

@bajtos 

Fixes #396
This is very brittle and also difficult to understand. All element selectors should be hidden behind View Object API.

Assuming you are trying to open the first datasource by clicking on it's name, the code should be something like

```
dataSourceEditorView.getAllDataSources()[0].openInEditor();
```

However, that does not reflect the GUI layout, does it? This would be closer to the real layout:

```
composerHomeView.getNavigationTree().getDataSources()[0].open();

// alternative
var allDataSources = composerHomeView.getNavigationTree().getDataSources();
var names = allDataSources.map(function(ds) { return ds.getName() });
expect(names).to.eql(['db']);

allDataSources[0].openInEditor();
```