Fix interpreting dates as valid timeuuid and introduce new methods to work with timeuuid

patch by slebresne; reviewed by thobbs for CASSANDRA-4936
Merge branch 'cassandra-1.2' into trunk

Conflicts:
	src/java/org/apache/cassandra/cql3/statements/SelectStatement.java
Support E notation for floating point numbers

patch by michalm; reviewed by slebresne for CASSANDRA-4927
Add missing mention of 4927 in CQL3 changelog
Merge branch 'cassandra-1.2' into trunk