Add new capnp compiler module.
Add new capnp compiler module.

This compiler compiles the schema into a erl_syntax:syntaxTree() type
which is far more flexible and easy to work with.

This will support output formats of .erl files as well as to compile
directly to a .beam file.

linearregression/ecapnp,kaos/ecapnp,reinfer/ecapnp,operable/ecapnp