ACCUMULO-3340 prefer IPv4 for MAC processes

  Add system property to MiniAccumuloCluster processes:
    -Djava.net.preferIPv4Stack=true
ACCUMULO-3291 Use target instead of /tmp
Merge branch '1.5' into 1.6

Conflicts:
	minicluster/src/main/java/org/apache/accumulo/minicluster/MiniAccumuloCluster.java
	minicluster/src/test/java/org/apache/accumulo/minicluster/MiniAccumuloClusterStartStopTest.java