Fix potential NPE in 2ndary indexes

patch by slebresne; reviewed by jbellis for CASSANDRA-6098
Merge branch 'cassandra-2.0' into trunk
Fix deletes potentially skipped in batches

patch by slebresne; reviewed by iamaleksey for CASSANDRA-6115
Merge branch 'cassandra-2.0' into trunk
warn, then drop queries exceeding a configurable number of tombstones
patch by jbellis; reviewed by slebresne for CASSANDRA-6117
Merge branch 'cassandra-2.0' into trunk
Add configurable metrics reporting
patch by Chris Burroughs; reviewed by Tyler Hobbs for CASSANDRA-4430
Merge branch 'cassandra-2.0' into trunk
fix build
Allow alter keyspace on system_traces

patch by yukim; reviewed by jbellis for CASSANDRA-6016
Merge branch 'cassandra-2.0' into trunk

Conflicts:
	src/java/org/apache/cassandra/service/CassandraDaemon.java
Tracing should log write failure rather than raw exceptions
patch by jbellis; reviewed by ayeschenko for CASSANDRA-6133
merge from 1.2
Merge branch 'cassandra-2.0' into trunk
avoid logging tombstone warnings during compaction
Merge branch 'cassandra-2.0' into trunk
change progressindicator members to CHM
patch by jbellis for CASSANDRA-6129
Merge branch 'cassandra-2.0' into trunk
6132
fix merge conflict