Merge PHLAK:hotfix/gravatar-trim-strtolower into master

PR #4976
PSR-2 - lowercase keywords (CONST to const)
Merge branch intellix:patch-5 into develop

Pull request #4983

Conflicts:
	library/Zend/ModuleManager/ModuleEvent.php

EVENT_MERGE_CONFIG was missing from this PR. Added it via conflict
resolution.