This makes it possible to access the creation functions
for the microwave inductor externally, so that it can be
used from GAL.
Unlike the Gap/Stub tools, the inductor tool is more interactive, and
doesn't just return a MODULE*.
Introduces a new directory in pcbnew called 'microwave' to better
isolate generic (i.e. canvas-agnostic) functions, and a namespace MWAVE
to avoid polluting the global namespace.
John Beard