Merge pull request #656 from FrozenNode/dev

Merge 4.12.0 into master
Merge pull request #664 from FrozenNode/dev

Merge 4.12.1 into master
Fix CSS syntax error in main.less that prevented most less compilers to run/build
Changing body to #wrapper to fix 3rd party style problems caused by too extensive rules
added / updated docs for new description option (edit-fields & filters)
added description paragraph to edit-fields if a value for description is set in model configs edit-fields array
added description paragraph to filters if a value for description is set in model configs filters array
added styles for the new description paragraph in edit-fields and filters
Changed method to get date and time in Field/Time

Instead of using "strtotime()" to create a timestamp a DateTime Class is used. This should solve some problems
with dates before 1970 or other dates further in the past.
Changed check for valid date.

All empty values will not be used to fill Time Field. This must be done because just checking
for null will cause today's date and time to be used if the field is empty.
change my space indenting to tabs
Added "use \DateTime as DateTime" to the top of File
Updated/improved hungarian language file
Serbian language lines fixed (remove 1 duplicate, added 1 missing)
allowing for the possibility of database.fetch to be associative
adding changelog for previous bugfix
validation should always check everything, not just the dirty attributes
adding vendor_alt for workbench testing
Fixing custom validation issues (Closes #719, #714, #699, #690, #616)
Merge pull request #695 from frzsombor/patch-6

Updated/improved Hungarian language file