Default no regions on master

Changes the configuration hbase.balancer.tablesOnMaster from list of table names that the can carry (with 'none' meaning no tables on the master) to instead be a boolean that is set to true if master carries tables/regions and false if it does not. If true, the master acts like any regionserver. If false, then the master carries no tables. This is the default for hbase-2.0.0. Another boolean configuration, hbase.balancer.tablesOnMaster.systemTablesOnly, when set to true, enables hbase.balancer.tablesOnMaster and makes it so the master hosts system tables exclusively (the long-time deploy mode of master branch and branch-2 up until this commit). UPDATE: This is broke. See HBASE-19785 . UPDATE2: Master carrying Regions does not work reliably, see HBASE-19828 . See HBASE-19831 , the issue to fix regions on Master The change of hbase.balancer.tablesOnMaster from String list to boolean and the addition of a simple boolean to enable system-tables on Master was done to constrain what operators might ask for via this master configuration. Stipulating what tables are bound to the Master server verges into regionserver grouping territory, a more robust means of specifying table and server combinations. Operators should use this latter if they want layouts more exotic than those supplied by the provided booleans.