Replaced three function calls with one.
Make use of single character variable syntax for the formal parameter variable.
Removed obsolete Makefiles.
Ignore only top level directories.
Replaced whole bunch for Makefiles with a single generic Makefile.

- No complex shell logic.
- "Source file shadowing" for all targets via vpath.
- Dependency handling.
- True incremental build.
- Don't write into source directories.
- Easy cleanup by just removing 'wrk'.
Replaced whole bunch for Makefiles with a single generic Makefile.

- No complex shell logic.
- "Source file shadowing" for all targets via vpath.
- Dependency handling.
- True incremental build.
- Don't write into source directories.
- Easy cleanup by just removing 'wrk'.
Added top level Makefile.
Avoid usage of cl65 for library build as it requires 'install'.