Merge refacto

[natacha-beck]

This PR is only for comments at this point and should not be merge.

This PR correspond to the work that @jonathanlurie and @natacha-beck have done on BrainBrowser to improve the UI.

We have removed the examples directory and replaced this one by 3 directories:

• BrainBrowserSurfaceUI: that contains all the specific code for the Surface viewer.
• BrainBrowserVolumeUI: that contains all the specific code for the Volume UI.
• BrainBrowserCommonUI: that contains common code for the Surface and the Volume UI.

We will have some issue of retro-compatibility especially in the Surface part of the code.

Some remarks:

• In src/brainbrowser/surface-viewer/modules/views.js: should we remove some functions like medialView, inferiorView... as said by Jonathan this one is specific to some models and does not work for generic models.
• Should we keep the rules of === for jshint?
• About jshint at this point, the *.js file in BrainBrowserSurfaceUI is not checked by jshint the code in the gruntfile is here, and we should (I will do that) fixed the syntax in this one.

Since this is a big PR I open this one now to let you have a look and make some comments. Before merging this PR we should make demo of the official website works with this PR, and then we can update merge here and update the website at the same time.

[natacha-beck]

This PR should be done on the dev branch.