Adding version checker error issue help (rebased onto develop)



This is the same as gh-752 but rebased onto develop.

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Adding how to avoid the automatic upgrade checker following mailing list question - http://lists.openmicroscopy.org.uk/pipermail/ome-users/2013-October/003980.html

(Also see https://github.com/openmicroscopy/ome-documentation/pull/516)