Clean up of length validation
Documentation improvements
Issue 624 - Check the mimetype ond filename of the revision when processing a file
allow the preview processor to use an internal address for global admin
rename internal address config variable
Use internal address for preview processor signed auth
Added a note about libpng, libjpeg and ghostscript dependencies for GraphicsMagick
Added links to new documentation
Missing punctuation
Merge branch 'master' into limits

Conflicts:
	node_modules/oae-content/lib/api.js
Merge pull request #620 from nicolaasmatthijs/limits

Length validation clean up
rename config property, fix error message
Merge pull request #600 from stuartf/internalAdminAddr

Add ability to configure admin server IP for preview processor requests
(Issue632) Don't reorder the etherpad server list
Adding more information about configuring etherpad clusters
Improve documentation of etherpad.js refreshConfiguration method
Merge pull request #624 from simong/624-reprocess-path

Error reprocessing preview of revision that is different mime-type than the latest revision
#334 - code cleanup + lowered log level on certain ImageUtil errors.
Merged master into 334-content-test-improvements.