Add default styles for today's date

[lostpebble]

Hi there,

I've just started using this and I notice that there is a class set on the calendar on the today's date tile (react-calendar__tile--now), but there are no styles applied to it which differentiate it from the others in any way.

Is this intentional? Would be nice to have the default styles include styling for that too. Maybe a very light grey, something subtle (when it is not the currently selected date).

[wojtekmaj]

Moved issue to wojtekmaj/react-calendar.