set commit time from commandline
New option: -datetime "2010-04-22T19:53:23Z" (RFC3339)

Adds imports to Commit.java to parse a timestamp String as a Long
Added support commits with timestamps in git-like formats, using the ParseTimestamp class
Merge pull request #2 from volaya/time

Added support commits with timestamps in git-like formats
Merge branch 'time' of git://github.com/mapmeld/GeoGit into mapmeld-time
fix javadoc format for ParseTimestamp.
Make the "Try to commit with timestamp in milliseconds" functional test scenario timezone agnostic.

For the commit -t argument, use a larger timestamp so it doesn't show up in log
as 1969-12-31 due to timezone differences depending on what timezone the build
box is in.