ACCUMULO-2791 Downgrade commons-codec to match that provided by Hadoop.

* Povide a core.util Base64 class to enforce the non-chunked behavior we rely on
* Changed to use codec 1.4 'shaHex' method
Merge branch '1.6.1-SNAPSHOT'

Conflicts:
	core/src/main/java/org/apache/accumulo/core/iterators/user/IntersectingIterator.java
	core/src/main/java/org/apache/accumulo/core/security/Authorizations.java
	core/src/main/java/org/apache/accumulo/core/util/Encoding.java
	mapreduce/src/main/java/org/apache/accumulo/core/client/mapreduce/lib/impl/ConfiguratorBase.java
	mapreduce/src/main/java/org/apache/accumulo/core/client/mapreduce/lib/impl/InputConfigurator.java
	server/base/src/main/java/org/apache/accumulo/server/master/state/TabletStateChangeIterator.java
	server/base/src/main/java/org/apache/accumulo/server/util/DumpZookeeper.java
	server/master/src/main/java/org/apache/accumulo/master/tableOps/Utils.java
	server/monitor/src/main/java/org/apache/accumulo/monitor/servlets/TServersServlet.java
	shell/src/main/java/org/apache/accumulo/shell/commands/AddSplitsCommand.java
	shell/src/main/java/org/apache/accumulo/shell/commands/CreateTableCommand.java
	shell/src/main/java/org/apache/accumulo/shell/commands/GetSplitsCommand.java
	shell/src/main/java/org/apache/accumulo/shell/commands/HiddenCommand.java
	test/src/main/java/org/apache/accumulo/test/randomwalk/shard/BulkInsert.java