Extend travis integration to test against Plone 4.1-4.3

Include following dependencies into tests:
  - ``plone.multilingual``
  - ``plone.multilingualbehavior``
  - ``archetypes.multilingual``
plone.app.dexterity requires z3c.form>=2.9.2dev0
Merge remote-tracking branch 'upstream/master'
Remove the quiet flag
Add version pins for Plone 4.1 and plone.app.dexterity 2.0
Merge remote-tracking branch 'upstream/master'

Conflicts:
	buildout.cfg
Update HISTORY
Remove buildout.dumppickedversions
Dependency update for Plone 4.1 build
Merge pull request #47 from saily/master

Restructure buildout