improve(model-editing): add validations and editing for Model and Diagrams


- [x] Model
  - [x] `title`
    - required and minlength of 2
  - [x] `version`
    - required and test against [Semver](http://semver.org/) RegExp pattern
  - [x] `authors`
    - required and minlength of 2

![image](https://cloud.githubusercontent.com/assets/1885333/5483846/8df336f8-8651-11e4-97c3-0f777b940f75.png)

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- [x] Diagrams
  - [x] `title`
    - required and minlength of 2
  - [x] show count of `elements`, `flows`, and `boundaries`
![image](https://cloud.githubusercontent.com/assets/1885333/5483929/fc2db5ce-8653-11e4-92a9-01130345e665.png)

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- [x] Improve intelligence of menu by opening and closing certain menus based on usage/click events