Cleanup: unused argument, variable warnings

Keymap: pressing leader key (Alt) again closes tool prompt

Provides a convenient way to close
if the tool prompt is opened by accident.

Fix compilation

Commited this cleanup by mistake

Merge branch 'master' into tmp-overlay-engine

Overlay Engine: Camera Background Images

Overlay Engine: Image Empties

Fix T71590: Closing file browser reopens previously closed render view

The render view window was never closed actually, just moved behind the
main window. It's properly closed now.

It should also behave more like expected when there already is a
temporary window open (e.g. Preferences).

GPencil Length modifier

This patch includes a modifiers that developed for NPR rendering.

- Length modifier that stretch/shrink a stroke.

Differential Revision: https://developer.blender.org/D5795

Prepare patch

Merge branch 'master' into greasepencil-object

Conflicts:
release/scripts/startup/bl_ui/properties_data_modifier.py
source/blender/gpencil_modifiers/MOD_gpencil_modifiertypes.h
source/blender/gpencil_modifiers/intern/MOD_gpencil_util.c
source/blender/makesdna/DNA_gpencil_modifier_types.h
source/blender/makesrna/intern/rna_gpencil_modifier.c

GPencil MultiStroke modifier

This patch includes a modifiers that developed for NPR rendering.

- MultiStroke modifier that generates multiple strokes around the original ones.

Differential Revision: https://developer.blender.org/D5795