add doc for compose
add $ as alias for compose
update flip documentation
update compose documentation
add constant function
add more assertions for curry
add constantArity, unary, binary, ternary and quaternary functions
modify getMeta to return entire meta data table when key is omitted and refactor call sites
add getArity function
refactor is* predicates to point-free style
add isUndefined, isNull and exists predicates
add getName function
add id function
replace eql with equal
expose isNull, isUndefined and exists predicates from Prelude
fix the is predicate to only check types not equality
add multimethods