Remove new_ prefix from MockMethod and ExpectsMethod closures.
Add additional validation of the mock_count option.
Remove TODO regarding validation of method_name argument to expects().

Although this is illegal:

  o = {}
  o.1a = -> "a function"

you can still do this:

  o = {}
  o["1a"] = -> "a function"
  o["1a"]()                  # => "a function"