ant scrip & nb project

[Xueming Shen]

Hi,

I added the ant build.xml and a nb project config file at 
make/netbeans/threeten.

The build script supports basic build/compile, test and jar. The 
threeten classes
can be compiled & tested without building the whole jdk8/jdk repository. 
You can
open the threeten nb project (inside the jdk8_threeten repository) in 
nb, edit, compile,
test without the need of building the whole jdk8. "coverage" can be 
added (with the
AllTest added), if really needed, but I just doubt the necessity. Roger, 
you need to
edit the build.properties to turn on the proxy, if run inside the oracle 
network.

A workaround has been added in TzdbZoneRulesProvider so the tzdb.jar can be
specified by -Djavax.time.zone.tzdbjar property. This is needed to run 
all those
TestNG tests against a java runtime that doesn't have all those threeten 
classes/tz
data.

Please help take a look. I will push tomorrow, if it's fine with you guys.

http://cr.openjdk.java.net/~sherman/jdk8_threeten/antbuild/webrev/

Thanks,
-Sherman