#1367304 by tim.plunkett, dereine: Allow to use arguments with multiple filter groups together. Therefore all filter groups get converted from 0,1 to 1,2 because 0 is made as a special group which has always AND which is then used by the arguments

#1372846 by frega, oadaeh: Add much better debug messages for creating instances of handlers/plugins

by dereine: Improve filter term_node by defining all used variables, removed unused variables and document much more stuff.

Revert "#1324580 by pcramba, dereine: Build the arguments first, so the default arguments exist on validate plugins"

This reverts commit 5aaf4534.

#1283960 by dereine: Add a override-selector on adding-item form, so you can choose whether you want to add to master or current display

#1324580 by pcramba, dereine: Build the arguments first, so the default arguments exist on validate plugins

#1353580 by damz: Use databaseType instead of db_driver() because db_driver() depense on hard coded assumptions