update swi.
use SWI's version data
Merge branch 'master' of ssh://yap.git.sourceforge.net/gitroot/yap/yap-6.3
UDI fixes
inf depth limit
imprive error handling.
sub_string hack
avoid PL_error
fix style_checking flags and especially variables.
names are now atoms, not sequences of codes
fix SWI exec issues and try to clean up the code a bit
update.
do not reset cintext before  cut
make SWI exec safer
try to reset stack
debugging
fix gprof undder a single running thread
Merge branch 'master' into debugger
signals
Merge branch 'debugger' of ssh://git.dcc.fc.up.pt/yap-6.3 into debugger