Make the "Merge shapefiles" tool correctly handle features without geometries.
INSTALL: update required flex version to 2.5.6 and links to windows version
Fix calculation of atlas map extent when set to fixed scale mode

Credit to m-kuhn for discovering the fix
Regenerate incorrect test images and reenable atlas tests for travis
backport adjust pluralization

backport https://github.com/geopython/MetaSearch/commit/83b88f67abb679501a238e4ab4ee344c3cdbf55d
translation script update:
* TRANSLATORS stats also needs lupdate run
* support numerus forms in python translation strings
fix windows build
fix script permissions
Fix slight offset in heatmap renderer
Merge pull request #1698 from jdugge/MergetoolEmptyGeometries

Make the Merge shapefiles tool correctly handle features without geometries
Remove useless statement
Don't enforce singleton behavior with Q_ASSERT

Fix #11726
Delete __init__.py
Delete utils.py
[processing] fix help file generator
[processing] fix parameter names in TauDEM algorithms
Fix Qt5 build