javascript code generation

[Sullivan MATAS <smatas viotech net>]

Hello,

I had to generate _javascript_ code for one of my project, so I made a _javascript_ code generation plug-in for dia. I think this may be usefull to someone else so I send you my patch.
The commit adds the JsRenderer class (inheriting from ObjectRenderer) to codegen.py.

I hope this will be usefull.

Sullivan MATAS
IT enginneer for Viotech communications
email: smatas viotech net