Add a new 'mask' feature renderer that can be used to invert polygon fills
Add missing .ui
Mask renderer: fix clone()
Mask renderer: do not store temporary features anymore
Mask renderer: make it work with on-the-fly reprojection
Mask renderer: reuse existing renderer as embedded
Mask renderer: rename to inverted polygon renderer
Inverted polygons renderer: add SIP
Add unit tests for the inverted polygon renderer
Merge pull request #1380 from Oslandia/mask_renderer

[FEATURE] Inverted polygons renderer