Stats processing: use urlparse to parse stats source

Review: http://codereview.adblockplus.org/5182947690807296/
Speed up stats processing by utilizing all available CPUs

Review: http://codereview.adblockplus.org/5182947690807296/
Stats processing: check for numbers correctly

Review: http://codereview.adblockplus.org/5182947690807296/
Stats processing: Use external gzip command to avoid loading everything into memory

Review: http://codereview.adblockplus.org/5182947690807296/