CodeMirror included for a task presenter editor. Refs #142
Unit Tests for CodeMirror in PyBossa Closes #142

This commit closes #142 issue as now it is possible to add a task presenter
using the PyBossa web interface, as well as the API. This commit uses
CodeMirror so users can see in real-time how their app will look like in PyBossa.
Merge pull request #310 from PyBossa/issue-142-webform-template

Issue 142 webform template