4206909 - adding Z_SYNC_FLUSH support to deflaters

[Xueming Shen]

Martin, Brandon, Alan

I still believe the best choice at this moment is to be a little more 
conservative, given the DOS.flush() has been
working in this behavior for decade. The proposed methods are good 
enough to serve the functionality required,
I don't think it is worth breaking the compatibility in this case simply 
because "it would be better...". We definitely
can consider to change the position should the feedback show this is not 
the case.

I will start the CCC if you guys are OK with the latest wording. The doc 
has been changed "slightly" compared to
last version, thanks for the comment from all of you.
 
http://cr.openjdk.java.net/~sherman/zipflush/webrev

Sherman