[cage] config/gen/core_pmcs.pm: ro pm, align comments

minor config/gen/core_pmcs.pm improvements:
  remove hard tabs in generated .pm
  set buffer-read-only:t in generated .pm
  rename internal code() to c_coda(), not used for .pm
  align numbers in comments in include/parrot/core_pmcs.h
[cage] more emacs ro [GH #1034]

in lib/Parrot/Configure/Compiler.pm genfile(), e.g. Makefiles