Microsoft-CISL/REEF — pull request #1012 by yingdachen (2014-10-03 04:55:47+00:00)
Title: change how dll files are extracted to speed up driver start-up time

currently we extract the dll files from jar file in a very efficient way that is dragging the driver start-up, especially when there are large number of dlls to be extracted and loaded.

this PR repalce the home-grown extracting method to standard IOUtilities.copy, which by default will use a reasonably-size buffer and improve the streaming writing efficiency.