Merge pull request #2719 from FinalAngel/fixes/2576

fixes issue #2576
increase queries
Merge branch 'fix-2514' of github.com:digi604/django-cms into fix-2514
Added changes to travis.yml and develop.py to allow setting of user model by environment variables.
fixes issue #2718
fixed an issue when hovering over a menu subchild removing the hover state
fixes #2675
Use Cache backend session only for tests
Merged upstream changes and fixed all failures
added double click maximize event to modal window title
jslint fix
allow using xvfbwrapper on linux for selenium tests
fixes the backend part
hide error when element is disabled
fixed tests
Merge pull request #2715 from yakky/feature/fix_2710_2

render_model and render_model_block elements are not hidden in structure mode
Added missing spaces in deprecation warning.
Merge pull request #2727 from timgraham/missing_spaces

Added missing spaces in deprecation warning.
Merge branch 'develop' into fix-2514
Merge branch 'develop' into fix-2514

Conflicts:
	cms/tests/toolbar.py