Don't index tombstones.

patch by Mikhail Stepura; reviewed by Aleksey Yeschenko for CASSANDRA-7828
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/db/index/SecondaryIndexManager.java
Merge branch 'cassandra-2.0' into cassandra-2.1.0

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/db/index/SecondaryIndexManager.java
Merge branch 'cassandra-2.1' into trunk
Implement -f functionality in stop-server.bat

patch by Philip Thompson; reviewed by Josh McKenzie for CASSANDRA-7901
Merge branch 'cassandra-2.1' into trunk
fix stress metrics format strings
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
In RowDataResolver, reduce calls to replies.size(), and use replies.peek() instead of replies.iterator().next()
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk

Conflicts:
	src/java/org/apache/cassandra/service/AbstractRowResolver.java
	src/java/org/apache/cassandra/service/RowDataResolver.java
Introduce new append-only concurrent collection, Accumulator, and use for AbstractRowResolver.replies

patch by benedict; reviewed by mishail for CASSANDRA-7873
Fix for CQLSSTableWriter concurrent writers

- When a KS is already defined but a CF is new, the CQLSSTableWriter
  now properly registers the CF with the Schema
- Add a test for concurrent CQLSSTableWriters