Cherry-Pick commits from dev branch:
Cumulative tasks set
Fix upload files vs WebDav
remove use cb_demosrc from demo core
remove depricated CommentNotifications plugin from casebox db
highlightjs
required fields in edit grid
dont hide default columns on empty DC response
default_DC, security fixes, required fields
use Arial font and increase font size and grid row height
ipc fixes
notifications sending based on "sent" flag
columns order, sender for comment mails
Extjs5 D&D between tree, grid and object window