Fixed a bug in the display of '-' that was causing horizontal lines to
be rendered incorrectly on the "Discover" page.

Removed some unused files from the build. This should shrink the .jar and .zip.

4f9255d698ae:
Fixed bug on the "Discover" page that caused lines to be drawn incorrectly
in some cases for graphs with rebased versions.

Use .zip instead of .tgz for source release.