when manually loading layers defer loading default style until the layers is
added to the registry so that the readCustomSymbology signal can be processed
by the edit widget registry (fixes #11516)
also restore style for file based layers (followup dfff717a0) and
use file name for GeoJSON layers (fixes #10711)
ftools: field uniqueness fix (fixes #11523)
fix graduated renderer crash (followup 6de53e51b)
fix modeller with saga tools
Merge pull request #1669 from gioman/tmp_fix_modeller_saga

fix modeller with saga tools
fix more graduate renderer crashes (followup d99d2fd97)
[TRANSUP] transifex translation updates

Signed-off-by: Werner Macho <werner.macho@gmail.com>
invert back toggle editing button in relation editor widget (fixes #11524,
followup b1a2bef1)
Less verbose debug output in layer tree model
update changelog for 2.6 release
Bump version to 2.7
support icons in map layer actions