Fix skipping columns with multiple slices

patch by frousseau & slebresne; reviewed by frousseau & slebresne for CASSANDRA-6119
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/db/columniterator/IndexedSliceReader.java
Fix test build
Disallow empty column names in cql
patch by dbrosius reviewed by slebresne for cassandra-6136
add concurrent sets to progressByHost (CASSANDRA-6129)
eliminate redundant classpath creation

Patch by eevans; reviewed by Anton Winter for CASSANDRA-6101
fix assertionerror from #6132
cleanup
merge from 1.2
fix addCallback for XDC requests too
merge from 1.2
one more consistencyLevel to pass along
merge from 1.2
last one?
Merge branch 'cassandra-1.2' into cassandra-2.0
Use Java7 file APIs to get saner exceptions etc.

And since windows does not support moving a file on top of another
existing file, remove the old file before moving.

Patch by marcuse, reviewed by jbellis for CASSANDRA-5383.
comment
Revert CASSANDRA-6132 (pushing to 2.0 only)
Merge branch 'cassandra-1.2' into cassandra-2.0
add consistencyLevel to callback in mutateCounter