Switch to swt4-gtk

Jeremy Bícharequested to merge
jbicha/syndie:swt4 into master

@mhatta Maybe there is a way to do this in debian/rules without needing to patch build.properties but I don't have enough experience with Java packaging to do that.

The app seems to run ok for me after this change, but I've never used this app before and it has an unusual user interface.

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