Move to version 3.3.1
fixed:
- Plot figures not saved as SVG
  https://bugs.launchpad.net/latexdraw/+bug/1393692
- Rotating plot figures does not work properly
  https://bugs.launchpad.net/latexdraw/+bug/1393694
- Mirroring plot figures does not work properly
  https://bugs.launchpad.net/latexdraw/+bug/1393695
- Cannot change the roundness of the rectangles' corners
  https://bugs.launchpad.net/latexdraw/+bug/1395469
Release 3.3.1
Merge branch '3.x'

Conflicts:
	latexdraw-core/net.sf.latexdraw.installer/pom.xml
	latexdraw-core/net.sf.latexdraw/pom.xml
	latexdraw-core/net.sf.latexdraw/src/main/net/sf/latexdraw/generators/svg/SVGShapesFactory.java
	latexdraw-core/net.sf.latexdraw/src/main/net/sf/latexdraw/glib/models/impl/LPlot.scala
	latexdraw-core/net.sf.latexdraw/src/main/net/sf/latexdraw/glib/models/interfaces/prop/IPlotProp.java
	latexdraw-core/net.sf.latexdraw/src/test/test/action/TestModifyShapeProperty.java
	latexdraw-core/net.sf.latexdraw/src/test/test/svg/loadSave/TestLoadSaveSVG.java