fixed gunzip error

It seems here the chunks need to be unzipped as they come in and not at the end. the commited code seems to fix the errors. Refer to http://stackoverflow.com/questions/10207762/how-to-use-request-or-http-module-to-read-gzip-page-into-a-string for my solution @rcrichton please review
We should treat uncompressedBody as a Buffer as below instead of a string.