Make CompactionsTest.testDontPurgeAccidentaly more reliable with gcgrace=0
Simplify auth setup and make system_auth ks alterable

Patch by Aleksey Yeschenko; reviewed by Jonathan Ellis for
CASSANDRA-5112
Merge branch 'cassandra-1.2' into trunk
Avoid throwing AE when hosts don't have a hostId
Patch by brandonwilliams, reviewed by iamaleksey for CASSANDRA-5197
Merge branch 'cassandra-1.2' into trunk
fix format string specifier
Merge branch 'cassandra-1.2' into trunk
drop keyspace from user-defined compaction API; patch by yukim reviewed by jbellis for CASSANDRA-5139
Stop compactions from handing during bootstrap.
Patch by brandonwilliams, reviewed by Vijay for CASSANDRA-5244
Merge branch 'cassandra-1.2' into trunk
comment
Merge branch 'cassandra-1.2' into trunk
revert CASSANDRA-5151 from 1.2
Merge branch 'cassandra-1.2' into trunk
comment
Merge branch 'cassandra-1.2' into trunk
fix compressed stream sending extra chunk; patch by yukim reviewed by mkjellman for CASSANDRA-5105
Merge branch 'cassandra-1.2' into trunk
Add CQL3-based implementations of IAuthenticator and IAuthorizer

Patch by Aleksey Yeschenko; reviewed by Jonathan Ellis for
CASSANDRA-4898
Merge branch 'cassandra-1.2' into trunk