v0.2.0

• add isKind, getKind functions, fix #29
• add to struct an assert on props argument, fix #30
• add sweet.js macros for all combinators, fix #32
• add a defaultDispatch function to union combinator, fix #33
• add overloading to func, fix #35

BREAKING

• now the kind of Any and all primitives is 'irriducible' fix #34
• uniform Any and primitives, export irriducible function, fix #34
• group all util functions in a util namespace, fix #36