Improves the literature module

o Moves classes
	- recipient, performer, institution to publisher in party.R
o Adds coercions and lists
	- recipient, performer, institution in party.R
o refactors citation classes
	- now the classes no longer call simple classes other in slots
	  simple type is used directly
o citation class coercions
	- refactors for new design
	- finishes book <-> s4

Belongs to issue #27
Merge branch 'master' into litrature
Changes typos in list names

o related to issue #27
Merge pull request #77 from cpfaff/litrature

Improves the literature module