Bug 836515 - Allow source compression to run while executing the script. r=jorendorff, a=tef+
Bug 835698 - 'Pre-open() and send the fd for app process's application.zip'. r=jduell, a=tef+
Bug 837715 - Reduce compression rate for js source. r=benjamin, a=tef+

This cuts the time to compress gaia-email-opt.js from 0.63 seconds to 0.33
seconds.  The result should still be smaller (391K from 321K before) than the
compressing with snappy or lz4 (528K), but decompression time will be worse.
Fortunately, this will only penalize Function.toSource() which I think is an ok
trade off.