fix(views): check if body_attrs are set before attempting to format them

Clears a log warning, cleans up the code and adds @uses to docs

Fixes #6298
fix(groups): check if handler is set in params before calling it

Clean up error logs results in an unset index
fix(views): only pass body_attrs if they are set

Cleaning up log notices
fix(hooks): remove event handler registration

Removes registration of an event handler that is not used in core, consequently reducing noise on the screen log

Fixes #6410
Merge pull request #6479 from hypeJunction/messy-log-cherrypick

Cleaning up some log noise
fix(install): fatal exception during installation

During the installation process 'normal' pages are drawn. Part if the
page is the metatag for sitedescription. This isn't available in $CONFIG
so the system goes to the database, which is unavailable.

fixes issue caused by 66f06919735e3de97b8262cc13c7044df755795b
fix(views): fix typo in $attrs var name
Merge pull request #6489 from hypeJunction/messy-log-cherrypick

fix(views): fix typo in $attrs var name
Merge pull request #6488 from jeabakker/fatal-exception-during-installation

fix(install): fatal exception during installation
docs(aalborg_theme): document change of content order

Fixes #5787
fix(core): fault in ElggPlugin contructor

The attibutes of an ElggPlugin are set too late to save all attributes
correctly.

fixes: #6426 and #6430
Merge pull request #6455 from jeabakker/wrong-initialization-of-ElggPlugin

fix(core): fault in ElggPlugin contructor
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