Misc fixes trying to get random to work

Has been failing with weird segfaults; hunting them down
2-arg form for long()
Fix a memory corruption in posix.urandom
In addition fix a valgrind uninitialized memory use warning
and close the opened file descriptor in posix.urandom
Teach abs how to handle longs
this let's us import random
Merge pull request #147 from undingen/mem_corruption

Fix a memory corruption in posix.urandom