chore(travis): Added travis script to check commit messages for commit ranges. Updated travis.yml.

Fixes #6381
Refs #5976
chore(git): Improved commit message script when being used as git hook.
chore(travis): Broke out the commit message validator into a class to make it testable.

Added tests for the git hook script and the travis script.
chore(docs): Updated best practices to include commit message reqs.
Merge pull request #6495 from brettp/travis_commit_msgs_6381

Have Travis check commit messages
feature(lightbox): added binding for elgg-lightbox-photo CSS class

Shortcut for data-colorboxOpts="{photo:true}" in HTML
chore(lightbox): replaced theme by another lighter

Using colorbox example 4: http://www.jacklmoore.com/colorbox/example4/

Fixes #6475
chore(lightbox): using elgg ajax throbber in lightbox

Fixes #4592
fix(lightbox): CKEditor was weird in lightbox

lightbox is not in .elgg-page and css wasn't overriding.
fix(lightbox): make lightbox scrollbar look better

File upload form in embed component was overflowing
Merge pull request #6504 from sembrestels/colorbox-theme

Colorbox theme
Merge pull request #6505 from sembrestels/lightbox-photo

feature(lightbox): added binding for elgg-lightbox-photo CSS class
fix(tests): Corrected the way the commit message tests are run.

Made more informative errors on phpunit failures. Corrected the way environment variables are passed to subprocess while testng. Allowed more merge commit label formats.

Fixes #6507
Merge pull request #6509 from Srokap/ticket_6507

fix(tests): Corrected the way the commit message tests are run.