add getCompiler and getLinker methods, to abstract from XSD.
add calc_source_md5 as it's more convenient especially for embedded
targets to add -DPLC_MD5="something" option at compile time than
to mess with editing binary.
add some more helper methods
These classes are intended for use server-side.
e.g. in a django view.py :
from pyjs.jsonrpc.django import JSONService, jsonremote