Implement CURRENT_DATE, LOCALTIMESTAMP, etc.
Add connect string property "timezone".
Use local timezone when returning Time, Date, Timestamp values from JDBC.

Conflicts:
	core/src/main/java/net/hydromatic/optiq/jdbc/OptiqConnectionImpl.java
	core/src/main/java/net/hydromatic/optiq/runtime/AbstractCursor.java
	core/src/main/java/net/hydromatic/optiq/runtime/SqlFunctions.java
	core/src/test/java/net/hydromatic/optiq/test/OptiqAssert.java
[maven-release-plugin] prepare release optiq-parent-0.4.12.2