Add Grunt build system

Using grunt to lint, concatenate and compress zenpen scripts.
Scroll value is not needed for ui bubble position. It is already included in boundary.top  (fixes #28)
Rewrote position code for the ui bubble (fixes #40 and #28)
Small changes for embeddable editor
Test file for ./js/embeddable.js
Version of ZenPen which is embeddable in any website
Remove unnecessary tag
Add <p> tag to fix blockquote bug
Add colorpicker example to test file
Merge remote-tracking branch 'potomak/feature/grunt'
Merge remote-tracking branch 'leon/master'
Merge remote-tracking branch 'prakt/bug-28'
Merged bugfixes by prakt