Add CKEditor-TeXZilla plugin

Link to CKEditor-TeXZilla: https://github.com/r-gaia-cs/CKEditor-TeXZilla

For this commit it was used c4e484c7f9fd71f5f313892a3da2919ee2b14722
Update based on version 1.0
Revert "Issue #1964: DB fields for generated content - quick links, zone nav, and body HTML"

This reverts commit 59557f71f8f8ca166fd80dc26db34c3f83ae2115.
Merge pull request #2063 from groovecoder/revert-content-fields

Revert "Issue #1964: DB fields for generated content - quick links, zone...
Hard restart for httpd in chief_deploy.py
Merge pull request #2065 from lmorchard/hard-restart-for-apache

Hard restart for httpd in chief_deploy.py
Merge pull request #2038 from r-gaia-cs/TeXZilla

Add basic math editing features
disable google-analytics.js with  'a' selector

exclude noisy javascript: links from tracking
Merge pull request #2066 from groovecoder/outbound-links-javascript

exclude noisy javascript: links from tracking