Add uthread_usleep which sleeps in microseconds.

Fixing a previous bug where rounding was causing inaccurate waiting.
wq
Fix simple warnings that did not include the right files.
CS multi-threaded and locking.

Note this is a basic version. Locking is not optimal and uses large
locks over large areas. Fine grained locking should improve the
performance of the CS server significantly. Holding off further
optimization if we are going to write it in GO.