Renaming hbase.rb to hbase_constants.rb because there are two hbase.rb files right now which is confusing. The constants are meant for shell, users shouldn't be using it directly. Anyways, this file is moved only in 2.0. In earlier branches, the files isn't renamed.
Remove omnipresence of formatter object since it is kind of a use-and-throw class. Commands should create
an instance, use it to format the output and discard it.
Minor 