Reduce repetition and fix a couple of typos.
PaperTrail 3.0.0 compatibility
catch and raise NameError exception
PaperTrail entries ordering. Fix #1840
Support for paper_trail custom version classes

Conflicts:
	lib/rails_admin/extensions/paper_trail/auditing_adapter.rb
changed scope to find the user
[Minor] Fix typo: explicitely -> explicitly

In exception thrown by the paper_trail auditing adapter.
Conflicts:
	lib/rails_admin/extensions/paper_trail/auditing_adapter.rb
Merge pull request #1948 from yuroyoro/backports_paper_trail_support

Backports PaperTrail compatibility and other fixies to rails-3.x