beta 3 (#3780)

* merge master - allow to upload twig invoice templates via UI
* support adding existing teams with same name
* permissions cannot be set right after role was created - fixes #3777
* allow to deactivate unique customer number validation - fixes #3762 
* invalid message when trying to edit locked or exported timesheets in calendar - fixes #3766
* updated icons and manifest - fixes #3761

public/robots.txt

@@ -1,5 +1,2 @@
-# www.robotstxt.org/
-# www.google.com/support/webmasters/bin/answer.py?hl=en&answer=156449
-
 User-agent: *
 Disallow: /