make uninstall should work

[andy5995]

Either make uninstall should work, or there should be a good alternative. Some info here

https://stackoverflow.com/questions/41471620/cmake-support-make-uninstall

This is dependent on #147 being completed first.

[andy5995]

The stackoverflow link above mentions using the install_manifest.txt file for finding the files that will be uninstalled. After doing a make install (see https://github.com/ZetaGlest/zetaglest-source/issues/210#issuecomment-420506466), I have that text file in my build directory. Here's what it looks like:

/home/andy/local/bin/zetaglest
/home/andy/local/share/man/man6/zetaglest.6
/home/andy/local/data/zetaglest/start_zetaglest_gameserver
/home/andy/local/data/zetaglest/glestkeys.ini
/home/andy/local/data/zetaglest/servers.ini
/home/andy/local/data/zetaglest/glest.ini
/home/andy/local/data/zetaglest/zetaglest.ico
/home/andy/local/bin/zetaglest_editor
/home/andy/local/share/man/man6/zetaglest_editor.6
/home/andy/local/data/zetaglest/editor.ico
/home/andy/local/bin/zetaglest_g3dviewer
/home/andy/local/share/man/man6/zetaglest_g3dviewer.6
/home/andy/local/data/zetaglest/g3dviewer.ico