moved ipc definitions to own file
updated user tests to use new ipc struct
some more encapsulation.  hopefully no bugs introduced
more encapsulation.  might be shaky -- testing should be done
added docs for ipc_send
added docs for ipc_recv
added docs to reply
added docs to mailbox file
added more mailbox docs
fixed mailboxes so replies get transferred
now have option field to make sure we don't do transfers to async messages
added tests, changed policy for async long messages (are ignored)
much better async test
quick fix to strcmp
rename async_test2
added manywait test
added mailbox docs
added descriptor table docs
added some files that were lying around