DONE Parameter conflict detector
DONE Parameter Parser
DONE Rename the functions to more sensible names
DONE s/p\//parameters-/g
DONE Modify parameter and package records
DONE Add the parsers to guix/parameters.scm
DONE Morphism Parser
DONE Parameter types indexable by numbers
DONE ! -> (p 0)
DONE _ -> match any nonzero type
DONE % -> package name
DONE package-with-parameters rewrite
