Bugfixes in SVN rev 130

Misc bugfixes in rev 130:

fix -datadir with relative path
autostart is now off by default except on windows
fix occasional "vector iterator not dereferencable" assertion when compiled with msvc
fix readlink compile warning on linux build
use sys/param.h and BSD define instead of __BSD__
-paytxfee switch, e.g. -paytxfee=0.01