Fix merge error
Typo - wrong variable name
Cleanup - use WT_File class instead of manipulating filesystem
Split tree/user preference getter/setter into two functions
Use consistent terminology (preference versus setting)
Allow the User object to work as a null object (e.g. for visitors)
Fix: #1377127 - Dates without a year in the monthly calendar
Tree settings cannot be null
Visitors have a null 'User' object
Fix #1377133 - Admin does not receive a mail for new user registrations
PHPDoc
Missed part of the WT_File::mkdir update
Prepare to convert included functions into classes so we can autoload them
Add asset-pipeline
Rewrite URLS in CSS pipelines