Revert LibList to a working state

Recent work on Liblist has resulted in an endless stream of fixes and fixes upon those fixes and fixes upon fixes upon those fixes.

* The only additional tests are testing garbage-in garbage out, not something useful.
* They are reporting spurious warnings to the end-users about said garbage
* I currently broken, and has been broken for other reasons before

I'm reverting it to the latest state that was known to be working without issues.
Delete unused PM_TO_BLIB macro
Space-quote pm_to_blib args
Absolutise all typemaps because with deep-located typemaps, eg
"lib/XS/typemap", if xsubpp is called from top level with
    $(XSUBPP) ... -typemap "lib/XS/typemap" "lib/XS/Test.xs"
it says:
    Can't find lib/XS/type map in (fulldir)/lib/XS
because ExtUtils::ParseXS::process_file chdir's to .xs file's
location. This is the only way to get all specified typemaps used,
wherever located.