[Java] Add support for second/microsecond/nanosecond timestamps in-memory and in IPC/JSON layer

[asfimport]

This is provided for in the metadata

https://github.com/apache/arrow/blob/master/format/Message.fbs#L85

and we have implemented it in C++/Python. In JSON, we may need to use strings if there are numerical precision issues

Reporter: Wes McKinney / @wesm
Assignee: Jingyuan Wang / @alphalfalfa

Related issues:

• Arrow release 0.2 (blocks)

_{Note: This issue was originally created as ARROW-477. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 303
#303