SP-258: Patch to deal with compilation issues in SIPUnit which appear to be to do with the type of a 'Timestamp'

Tested with

java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)
SP-258: Experimental waitForDisconnectResponse logic

Based on the following thread: https://sourceforge.net/p/cafesip/discussion/467762/thread/fbf155f6
AST-706: Change target to destdir in Maven config.

target is now a version number.
AST-706: Missing disconnect() wrapper
AST-706: Pass internal trace messages on to a version of log4j with trace support.

Support user-defined log4j compatible logger -
We needed to bump the log4j dependency on a bit for this support.
AST-706: Problem processing some events, such as BYE

We're not entirely sure about this logic, but it prevented us seeing BYE requests between agents.
The BYE was received, but waitForDisconnect() timed out.  This change appears to correct it.