returns all pc-sets with pc-count pitch-classes with description containing search-term

returns a pc-set given either the index or a keyword of common-set. returns empty map if not found.

The table of pitch class sets from Larry Solomon
  https://web.archive.org/web/20170710011331/http://solomonsmusic.net/pcsets.htm

  *	The set is a mirror (see Glossary).
  <	The set has a complement with the same name ending1
  (4)	(1) The set has only 4 different unique transpositions, as opposed to the normal 12. (2) when occurring after 'comb', indicates the transposition of comb when the set is in prime form.
  B	(at the end of a set-name) The set is the inverse of the set without the B and has the same IV.
..15	This is a Z set whose counterpart (having the same IV) is ordinal number 15 of the same cardinality. For hexachords this number also designates the set complement.
  comb  	This is a hexachord that is combinatorial.
  comb RI	This hexachord is combinatorial with RI (the number in parentheses indicates the transposition of comb form when set is prime form)
  all-comb	The set is known as an all-combinatorial set (see Glossary).
  AAAA5	The last two sets in the table have their IVs designated in hexadecimal; A=10, B=11, C=12