README.md - added information about 8-digit hex functionality
README.md - added information about 8-digit hex functionality

bgrins/TinyColor,pandabamboo90/TinyColor,vxvinh1511/TinyColor,dabassett/TinyColor,weepy/TinyColor,GerHobbelt/TinyColor,bgrins/TinyColor,vxvinh1511/TinyColor,mwcz/TinyColor,GerHobbelt/TinyColor,pandabamboo90/TinyColor,mwcz/TinyColor,dabassett/TinyColor,weepy/TinyColor