[Xastir] Internal Shapelib code removed from Xastir sources

[Curt Mills]

At Tom Russo's request I removed the internal Shapelib code from Xastir.
It's been a long time coming really. We don't need it anymore since most
distributions have Shapelib and Shapelib-dev available as packages, plus
the internal Shapelib code was messing up a few things in our build system
("make distclean" for one).

If anyone was depending on that Shapefile map rendering in their Xastir,
they'll need to install Shapelib and Shapelib-dev packages the next time
they do a Git update and a compile else Shapefile maps (and weather alerts)
will be gone. Check the summary page at the end of "./configure" every time
to see what you will or will not be compiling in.

-- 
Curt, WE7U        http://we7u.wetnet.net        http://www.sarguydigital.com