[#1483] add extension writing tip about avoiding plugin importing
Update strings files before CKAN 2.2 call for translations
Update translations from Transifex before 2.2
Merge pull request #1483 from ckan/1483-writing-ext-tip

Add a tip about testing extensions
[#1526] Fix some tests broken by commit b117294987
Merge branch 'master' of github.com:ckan/ckan into improved-group-factory