add licensing for buttons.less
add licensing for buttons.less

linkedin/hopscotch,kate2753/hopscotch,thbar/hopscotch,Axosoft/runningjumpscotch,Axosoft/runningjumpscotch,dataquestio/hopscotch,k10world/Hopscotch,thbar/hopscotch,stephenh/hopscotch,zimmi88/hopscotch,Xephi/hopscotch,kate2753/hopscotch,renatolotfi/hopscotch,stephenh/hopscotch,adcade/hopscotch,sganz/hopscotch,slietz/hopscotch,ryanone/hopscotch,zimmi88/hopscotch,renatolotfi/hopscotch,slietz/hopscotch,adcade/hopscotch,Xephi/hopscotch,sganz/hopscotch,dataquestio/hopscotch