Fix export to JPEG

The JPEG format exports files with alpha because only JPG extension is
managed.
Add LinkageError amd NullPointerException exception.
Added test file
Updated all versions of plugins
Merge pull request #16 from diodfr/master

Fix export to JPEG
Merge pull request #19 from gg0/sweethome3d

Add LinkageError amd NullPointerException exception.
Fixed #18
Apidocs published on gh-pages
Moved site to gh-pages branch
Disabled site plugin
Update UpdateApidocsOnPages.md
Update UpdateApidocsOnPages.md
Update README.txt
Updatd to 2.3-SNAPSHOT
Merge branch 'master' of github.com:freehep/freehep-vectorgraphics
Updatd to 2.3-SNAPSHOT
Fixed #15
LinkageError is in fact a Throwable, so now we catch all
Merge branch 'master' of https://github.com/freehep/freehep-vectorgraphics

Conflicts:
	freehep-graphics2d/src/main/java/org/freehep/graphics2d/PixelGraphics2D.java

(just catch Throwable instead of enumerating any possible exception)