[SP-478] Update version for release build.
[SP-484] Patch request for PDI-7172 - Jobs are not removable from PDI (within Spoon)
[SP-479] Version back to 5.0-SNAPSHOT for ongoing dev and nightly builds

Cleanup. Build system now has a work around to set this automatically for release builds.
Merge pull request #38 from pavel-sakun/SP-484

[SP-484] Patch request for PDI-7172 - Jobs are not removable from PDI (within Spoon)
Update Const.java