Move fantasy-land methods to the prototypes and implement Node.js inspect()

[cAttte]

hi! this PR closes #745 and closes #744.

here's an example of how the changes affect debugging output. given this script:

console.log('nothing:', Nothing)
console.log('something:', Just({ a: 3 }))

before this PR, the output was:

(expand)

nothing: {
  'fantasy-land/equals': [Function: equals],
  'fantasy-land/map': [Function: map],
  'fantasy-land/ap': [Function: ap],
  'fantasy-land/alt': [Function: alt],
  'fantasy-land/chain': [Function: chain],
  'fantasy-land/reduce': [Function: reduce],
  'fantasy-land/extend': [Function: extend],
  'fantasy-land/filter': [Function: filter]
}
something: {
  __value: { a: 3 },
  'fantasy-land/equals': [Function: equals],
  'fantasy-land/map': [Function: map],
  'fantasy-land/ap': [Function: ap],
  'fantasy-land/alt': [Function: alt],
  'fantasy-land/chain': [Function: chain],
  'fantasy-land/reduce': [Function: reduce],
  'fantasy-land/extend': [Function: extend],
  'fantasy-land/filter': [Function: filter]
}

after a37c7c9 (fantasy-land), and in the browser, the output is:

nothing: {}
something: { __value: { a: 3 } }

after a7e20f0 (inspect), only on node.js, the output is:

nothing: Nothing
something: Just({ a: 3 })

compare with the current inspect():

nothing: Nothing
something: Just([object Object])

[gigobyte]

Thanks a lot, great quality of life improvement!