switch DB Manager's SQL editor to QgsCodeEditorSQL
[FIXED] #11572 Filter Legend By Map Content doesn't maintain point displacement legend

The fix from https://github.com/qgis/QGIS/pull/1673 has to be enhance to have
 something more generic.

This fix add methods to QgsPointDisplacementRenderer:
* capabilities
* symbolForFeature
* originalSymbolForFeature
* symbolsForFeature
* originalSymbolsForFeature
* willRenderFeature
case insensitive autocompletion
Merge remote-tracking branch 'rldhont/filter_legend_displacement_point2'

Conflicts:
	src/core/qgsmaphittest.cpp
Add note about QgsMapCanvas::refresh() behavior
[TRANSUP] some fixes and improvements for transifex including renamed and deleted ts files

Signed-off-by: Werner Macho <werner.macho@gmail.com>
add missing ts files (fixes #11662)
Merge pull request #1686 from alexbruy/dbmanager-sqleditor

switch DB Manager's SQL editor to QgsCodeEditorSQL
More README to README.md

And add travis build status
homogenize icons related to managing project and global scale lists
Fix CPack path to README.md
add shortcuts to some Processing actions
Fix atlas with fixed scale