message: Change moment type defenitions in proptypes table
diff: @@ -101,7 +101,7 @@ Here is a list of available props
  Prop | Type | Default | Definition
  ------------ | ------------- | ------------- | -------------
  value | date | new Date() | Datepicker value
  -format | string | 'MMMM Do' | Moment format string for input
  +format | string | 'MMMM Do' | Format string for input
  autoOk | boolean | false | Auto accept date on selection
  disablePast | boolean | false | Disable past dates
  disableFuture | boolean | false | Disable future dates
  @@ -110,7 +110,7 @@ openToYearSelection | boolean | false | Open datepicker from year selection
  minDate | date | '1900-01-01' | Minimum selectable date
  maxDate | date | '2100-01-01' | Maximum selectable date
  onChange | func | required | Callback firing when date accepted
  -returnMoment | boolean | true | Will return moment object in onChange
  +returnMoment | boolean | true | Will return moment object in onChange (if moment utils using)
  invalidLabel | string | 'Unknown' | Displayed string if date cant be parsed
  emptyLabel | string | '' | Displayed string if date is `null` (e.g. after clear)
  okLabel | string | 'OK' | The label for the ok button
  @@ -178,7 +178,7 @@ rightArrowIcon | react node | `<Icon>keyboard_arrow_right</Icon>`| Right arrow i
  dateRangeIcon | react node | `<Icon>date_range</Icon>`| Date tab icon
  timeIcon | react node | `<Icon>access_time</Icon>`| Time tab icon
  ampm | boolean | true | 12h/24h view for hour selection clock
  -shouldDisableDate | (date: Moment) => boolean | () => false | Allow to disable custom date in calendar
  +shouldDisableDate | (date: Moment | Date) => boolean | () => false | Allow to disable custom date in calendar
  keyboard | boolean | false | Allow to manual input date to the text field
  keyboardIcon | react node | `<Icon>event</Icon>` | Keyboard adornment icon
  maxDateMessage | string | 'Date should not be after maximal date' | Maximum date error message for keyboard input
  