(runtime) Build only needed files in library
(backends) Add the new COMPA backend
(compa) Declare backend extensions points
(c) Fix all methods visibility
(xtend) Move some extension methods in CommonPrinter

These methods can now be used by all backends
(c) Replace redundant code by an extension method
(c) Replace an inline FOR by a join()
(compa) Add InstancePrinter
(c) Flatten some recursive calls

Replace them by true for loops
(compa) Implements COMPA backend
(backends) Check MD5 for files before exporting them
(compa) Last fixes, remove dead code in source produced
Merge branch 'compa_backend'