PARQUET-12: Add format support for additional converted types.

Author: Jacques Nadeau <jacques@apache.org>

Closes #3 from jacques-n/PARQUET-12 and squashes the following commits:

7001502 [Jacques Nadeau] Remove micros implementations until everyone is agreed on micros versus nanos.
b0e067c [Jacques Nadeau] PARQUET-12: Add format support for additional converted types.