#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

#439238 by dereine: If a path is renamed but part of the destination redirect the user to the new path

Revert "Issue #1222324 by damz, agentrickard, bojanz, dereine: Find a proper way to have multiple access tags per view and support relationships."

This reverts commit 5c1de214.

Issue #1222324 by damz, agentrickard, bojanz, dereine: Find a proper way to have multiple access tags per view and support relationships.

As dbtng doens't have base tables per tag this patch adds an ugly
workaround, that runs the query altering manually foreach tag.

#1176048 by filijonka, tim.plunkett, dereine: Let the remove button respect chaning of the override selector, yeah!

#1257376 by dereine: Don't run the preview on page load, but adding a seperate request for it.\n\nThis will catch a lot of possible issues with sql errors and can improve the speed of the editing, if you have unchecked the automatic-preview checkbox