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

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="WAMP://127.0.0.1:8888#Automation#2534667845">
  <TargetType/>
</BeremizRoot>