[threeten-dev] Java.time -Xlint warning cleanup

[roger riggs]

Hi,

An ongoing goal is to cleanup the JDK build so that compiles do not produce
warnings.  They may not go in with the rest of the current updates but I 
wanted
to understand the impact.

The bulk of warnings in java.time are related to unchecked casts.
But some API changes seemed to be the better solution than just
suppressing the warnings.

Please review:

http://cr.openjdk.java.net/~rriggs/webrev-unchecked-cleanup-8020418/

Thanks, Roger