CQL3: support pre-epoch longs for TimestampType

patch by Mikhail Stepura; reviewed by Aleksey Yeschenko for
CASSANDRA-6212
CASSANDRA-6212 CHANGES.txt
Add reloadtriggers command to nodetool

patch by Suresh; reviewed by Aleksey Yeschenko for CASSANDRA-4949
Fix altering column types

patch by slebresne; reviewed by iamaleksey for CASSANDRA-6185
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/config/ColumnDefinition.java
	src/java/org/apache/cassandra/db/marshal/CompositeType.java