Today

[nebaz]

1. text "today" can be a react.element
2. ability to hide the today button

[felixakiragreen]

Thank you for submitting a PR! A few questions before I merge it:

1. Can you explain the use-case for wanting the text "today" to be a React.element?
2. If it can be a React.element, does it still make sense for it to be buried in options.format.today or should it be its own prop?

[nebaz]

for example, translate text "today" Instantly. To do this, I need to keep the text into react.element.