This reverts commit 2a84d259.

Broke regression test on test_hwm.cpp.

These changes cause an assertion in lb_sendpipe() when executing the test_security_plain testcase.

This reverts commit 9ae6a91f.

- used msleep (10) in most places instead of zmq_sleep (1)
- may cause failures on slower machines
- to change, modify SETTLE_TIME in testutil.h
- tested down to 1 msec on fast boxes