Remove distinction between module name and path
Remove distinction between module name and path

The Makefile was meant to use two variables to identify a model. One
identifier for use in variable names, and another in paths. Since most
reasonable file name characters are valid in Makefile variable names,
this distinction was unnecessarily confusing, and can be removed.

cventus/otivm,cventus/otivm,cventus/otivm