Merge pull request #1 from divio/develop

updating fork from master
fix for setting inheritance on a page
temp reverting #2606 change as it is blowing up
removing the spaceless tags as it mucks with html output
Merge pull request #2 from daegun/removeSpaceless

removing the spaceless tags as it mucks with html output
Merge pull request #3 from divio/develop

merging main fork into personal fork
fixes the backend part
merging main develop branch to test
Merge pull request #5 from daegun/test

merging main develop branch
reverting temp import module change
adding tests
remove tabs
Separated PlaceholderAdmin into a mixin class to be used together with admin.ModelAdmin
Fixed a timing problem which occurend sometimes
Replaced PlaceholderAdmin against PlaceholderAdminMixin together with admin.ModelAdmin
Replaced PlaceholderAdmin against PlaceholderAdminMixin in unit tests
Replaced PlaceholderAdmin against PlaceholderAdminMixin in docs
fixed typo
Renamed FrontendEditableAdmin to FrontendEditableAdminMixin for using consistent terminology
added a page settings button instead of publish if there is no title