Detect undeclared dependencies #15
Description
Custom modules frequently uses code from other custom modules without declaring its dependency, assuming both are always deployed.
This check attempts to detect such missing dependencies.
In its first versions it will not attempt to be exhaustive, but just identify (a) function calls (b) in module files (c) calling functions (d) in other module files. Later versions could track OO code and/or check availability with the autoloader.