ACCUMULO-1785 adds ACCUMULO_VERIFY_ONLY mode to bin/config.sh.

* When set, won't write to local filesystem
 - skips mkdir for ACCUMULO_LOG_DIR
 - skips standalone mode checks
 - skips writing to missing tracers file
* Other behavior changes
 - if GC was set, we won't overwrite it
 - if MONITOR was set, we won't overwrite it

Signed-off-by: Keith Turner <kturner@apache.org>
Merge branch '1.4.5-SNAPSHOT' into 1.5.1-SNAPSHOT

Conflicts:
	bin/config.sh
Merge branch '1.5.1-SNAPSHOT' into 1.6.0-SNAPSHOT
ACCUMULO-802 Apply Sean Hickey's patch (v5)
ACCUMULO-802 Fixed NullPointerException during CloneTable due to loadbalancer trying to get the configuration before the namespace is put under the table in zookeeper. Fixed another NullPointerException with the -tn shell option for online, offline, and du. Added -tn option to shell config command. First attempt at adding a randomwalk test for namespaces, fails currently.
ACCUMULO-802 Updated ShellServer test with code that didnt fit in the patch correctly
ACCUMULO-802 Fixed a problem with RandomWalk's CloneTable, forgot to have it create a namespace. Randomwalk doesn't fail as fast, but still doesn't run correctly
ACCUMULO-802 Many small fixes. Largest change was adding CloneNamespace which clones all the tables in a namespace to a new namespace.
ACCUMULO-802 Lookup namespace config dynamically per table
ACCUMULO-802 Added global shell completion for table namespaces with -tn (just like -t for tables). Fixed problem with RenameTable to a new namespace copying over the old namespace configuration to the new table. Many other minor fixes. A few tests fail due to CloneTable not working until ACCUMULO-1565 is fixed
ACCUMULO-802 fixed an import problem in RenameTableNamespace. Commented out problematic code for cloning tables until ACCUMULO-1565 is fixed
ACCUMULO-802 added -tn option to the TablesCommand to allow listing of tables within a specific namespace
ACCUMULO-802 added a Total to the DUCommand to know the disk usage of a whole namespace or for everything
ACCUMULO-802 added iterators and constraints for namespaces. Currently the constraint part of the test fails, but iterators work.
ACCUMULO-802 working on namespace constraints, test currently fails, doesn't update tables constraints until something else triggers a reload.

Conflicts:
	server/src/main/java/org/apache/accumulo/server/conf/TableNamespaceConfiguration.java
	test/src/test/java/org/apache/accumulo/test/TableNamespacesTest.java
ACCUMULO-802 updated ConstraintCommand to work with namespaces
ACCUMULO-802 changed TableNamespaceConfiguration to update it's tables confs when it changes
ACCUMULO-802 added TableNamespaceConfWatcher
ACCUMULO-802 finished adding constraints to namespaces, works correctly.
ACCUMULO-802 removed useless line from testing