applied the user directories support patch, disabled by default. 'make DO_USERDIRS=1' to enable it.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1013 af15c1b1-3010-417e-b628-4374ebc0bcbd
update docs after r1013

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1014 af15c1b1-3010-417e-b628-4374ebc0bcbd
add missing header

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1015 af15c1b1-3010-417e-b628-4374ebc0bcbd
use getcwd() or some equivalent for host_parms->basedir instead of '.' (from uhexen2)

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1016 af15c1b1-3010-417e-b628-4374ebc0bcbd