Merge remote-tracking branch 'refs/remotes/origin/bugfix-PLUGIN_ASSETS' into dev-v3

Conflicts:
	includes/base_controls/QControlBase.class.php
Merge remote-tracking branch 'refs/remotes/origin/feature-ComposerPlugins' into feature-ComposerPlugins
Moving autoloader so our autoloader executes first.
Adding ability for plugins to point to other composer directories for assets, and making sure our autoloader goes first. This allows the project/includes/plugins directory to override the default.
Adding ability for namespaced plugins to be overridden
Changing plugins to plugin for namespace reasons.
Moving plugins to plugin for namespacing
Merge branch 'refs/heads/feature-ComposerPlugins' into dev-v3