Retrieve the current system time
<response> <version>2</version> <code>200</code> <text>OK</text> <currentTime>1270614730908</currentTime> <data class="time"> <references/> <time> <time>1270614730908</time> <readableTime>2010-04-06T21:32:10-07:00</readableTime> </time> </data> </response>