Merge xgcd_partial from qfb branch.
Added prototype for xgcd_partial to fmpz.h.
Add missing const to prototype.
Fix bug in fmpz_is_prime_pseudosquare on 32 bit machine.
Merge remote-tracking branch 'wbhart/trunk' into trunk
Use slong instead of long in _si function prototypes.
Merge remote-tracking branch 'wbhart/trunk' into trunk