- Many changes to make Hept2mls, mls2obc, etc
compile with the api changes
- Added Callgraph_mapfold: starting from a main
program, generates the list of instances of each
node necessary and creates them.
- Mls2seq deals with giving to the code generators
the correct source (mls or obc, wit or without
static parameters)

It is now possible to use parametrized nodes that 
are defined in other files. For that to work, the 
first file has to be compiled to an object file:
	heptc -c mylib.ept
which creates a mylib.epo file. Compiling the main
file will then generate all the instances of 
parametrized nodes from the lib (only the called 
nodes will be compiled, but all the nodes in the 
main file are compiled).