Support alpha in Hex for color picker
I was working with react-color and found some issues about the alpha color, I manage to solve them by converting rgba to hex. and found that hex values don't support alpha values.
I mean a hex value support 6 characters for RGB but some software and in CSS hex value can have 8 characters with the last 2 characters are for the alpha value.
it would be useful to have an auto-convert from RGBA to HEX without losing the alpha value.
