add test for setAlpha return value - #48
add test for setAlpha return value - #48

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