This reverts commit ddfbb4f5.

revert to using a single way for finding the libdir, as my assessment of the OSX bug turned out to be wrong

* the original namespace-collision checker only worked for abstractions
* trying a new namespace-collision checker revealed about 80 new clashes.
  Since there are so many it's probably too disruptive to remove them.
* probably need to revert the namespace clash abstraction removals

repo cleanup: remove tcl/tk build infrastructure and scripts, old patches, automated build scripts for pd-extended, old gui plugins, and unnecessary install-time dependencies

Add missing dlls to Windows installer, add dynamic lib extensions for Windows and OSX to scripts/load_all_binaries.pd

*forgot to add two files

 *hopefully fixed the remaining conflicts between pd-extended deb and pd-l2ork deb