Merge branch 'master' of ssh://yap.git.sourceforge.net/gitroot/yap/yap-6.3
itry to use size_t
fix overflow handling bugs.
document load_db
fix worker_id assignment in threads
fix compilation without threads
fix compilation of prism+odbc.
fix call to undefined halt/1.
fix swi falgs and set_prolog_flag/2.
remove debugging support
have a separator cell not to confuse the gc.
add debugging hooks to gc
avoi calls to inityaamregs.
New work on UDI
packages udi as module
Changes Rtree so almost working
fix compilation on sequential win32
add  SWI PL_uninstantiatin_error
Rtree working as a plugin in UDI
UDI: more work
improve java support