[lower RAM] Compile jade outside of runtime

Analysing the heapdump from the proxy show a good chunk of memory was occupied by various versions of UglifyJS required by Jade.  

This PR builds .Jade files to .JS during cake build and thus do not require('jade') at runtime, avoiding excessive memory usage. This brings down the heapdump from ~13Mo to ~9Mo.

RSS usage is still too damn high, this is most likely caused by a C++ compiled module doing its own malloc.