mockup split into core package and collection of patterns

# Purpose

Main reason for this split is that anybody developing nes pattern can only depend on minimal set of tools that are needed.

# Changes
(summary)

- create ```mockup-core``` package which will include: pattern registry, base pattern, docs app.
- ```mockup-core``` parts should be tested
- new design and code for docs app (Bootstrap+Backbone+ReactJS)
- update all bower and npm dependencies to latest
- simplify Gruntfile.js