basex: new package

BaseX is a very fast and light-weight, yet powerful XML database and
XPath/XQuery processor, including support for the latest W3C Full Text
and Update Recommendations. It supports large XML instances and offers a
highly interactive front-end (basexgui). Apart from two local standalone
modes, BaseX offers a client/server architecture.

Homepage: http://basex.org/

Implementation notes:
 - I'm using the pre-built java package (because it's simple)
 - I copied the basex.svg icon file from the Ubuntu package because I
   couldn't find it anywhere else. It's 9.3 KiB.