1.5.1.2 HttpClient method naming changes to comply with common conventions, and TimeUtils improvments

In this release, method setRequestProperty() of class HttpClient was deprecated, and a new method setRequestHeader() was added. The functionality of both those methods is identical, just the method name is more compliant with common conventions. Also in class TimeUtils method sleepFor() no longer just "swallows" and ignores InterruptedException, but if InterruptedException occurred, the method interrupts the current thread, so the thread interruption mechanism continues to work uninterrupted (pun intended).