[~] DEVELOP INIT
chore(travis): Run bower install twice to make sure it does
Like angular/angular.js is doing.

This is a work-around for Bower/Node.js issue (https://github.com/bower/bower/issues/830). We run `bower install` twice, as the probability of failing twice in a row is very low.
fix(test): Resolve optional ngModel testing
style(test): Reformat the sources
refactor: create CodeMirror with the default contructor !
No more using [`CodeMirror.fromTextArea`](http://codemirror.net/doc/manual.html#fromTextArea) to create the CodeMirror editor.
Direct copy of the original element attributes to the created CodeMittir editor
style(test): Flatten tests
Remove unnecessary `describe`
chore: Initialise the editor value with the element content
chore(demo): Update demo
docs: Update README
The CodeMirror events are better handled in the `onLoad` function.