ACCUMULO-3340 Restrict ZooKeeper binding in MAC

  Forces ZooKeeper to bind only to 127.0.0.1 in MiniAccumuloCluster,
  instead of the default, which is to bind to all interfaces.
Merge branch '1.5' into 1.6

Conflicts:
	minicluster/src/main/java/org/apache/accumulo/minicluster/MiniAccumuloCluster.java
Merge branch '1.6'
ACCUMULO-3338 Fixing classpath items for busbey.
Merge branch '1.6'

Conflicts:
	assemble/bin/bootstrap_config.sh
ACCUMULO-3342 Remove check for tracer in ZK

  Removes the MiniAccumuloCluster check to see if an existing instance is
  running via the existance of a tracer registration. Tracers aren't really part
  of "Accumulo", so much as an extra service, which also registers itself in ZK.
  As such, they don't really determine whether Accumulo is "running", and in any
  case, it is not running by default in MiniAccumuloCluster for the tests that
  are failing, so it's expected that this directory will not exist.
ACCUMULO-2916 Update docs related to ZooKeeper version
ACCUMULO-3341 Make deletetable remove any tables in the accumulo namespace before attempting deletion.

Also fixed the test package from 'command' to 'commands'.
Merge branch '1.6'

Conflicts:
	core/src/test/java/org/apache/accumulo/core/util/shell/command/FormatterCommandTest.java
	core/src/test/java/org/apache/accumulo/core/util/shell/command/HistoryCommandTest.java
	core/src/test/java/org/apache/accumulo/core/util/shell/commands/FormatterCommandTest.java
	core/src/test/java/org/apache/accumulo/core/util/shell/commands/HistoryCommandTest.java
	shell/src/main/java/org/apache/accumulo/shell/commands/DeleteTableCommand.java
	shell/src/test/java/org/apache/accumulo/shell/command/FormatterCommandTest.java
	shell/src/test/java/org/apache/accumulo/shell/command/HistoryCommandTest.java
ACCUMULO-3347 Log a message when a sesion is torn down due to it being idle or not accessed.
Merge branch '1.6'

Conflicts:
	server/tserver/src/main/java/org/apache/accumulo/tserver/TabletServer.java
ACCUMULO-3351 Try to reset the writer if we don't have one but the table exists.

We have to avoid the case where we spin indefinitely trying to process
traces (but cannot because we don't have a writer). If we don't have
a writer, but the trace table exists, try to get a new writer.
ACCUMULO-3355 Catch the case when we find no traces and quit early.

If we don't quit early, we end up creating this absurd date and sending
it back to the user. Also fixed two tests that were unnecessarily
nuking the entire trace table. The Scanner they create is bounded for
their trace session; there is no reason to delete the rest of the records.
Merge branch '1.6'

Conflicts:
	server/tracer/src/main/java/org/apache/accumulo/tracer/TraceDump.java
ACCUMULO-3358 Start the verify thread.
Merge branch '1.6'
ACCUMULO-3351 Remove use of deprecated trace code in 1.7.x