Update README.markdown
Update README.markdown

Fixed the sample image url to my repository uri for now, before getting into master branch.
GuanKunLuo/FlatUIKit,imjerrybao/FlatUIKit,applexiaohao/FlatUIKit,lydonchandra/FlatUIKit,ajrulez/FlatUIKit,nathankot/FlatUIKit,Grouper/FlatUIKit,somedev/FlatUIKit,brextonpham/FlatUIKit,fromeflow/FlatUIKit,ChaosCoder/FlatUIKit,hessu/FlatUIKit,tuanpa199/FlatUIKit,zyprosoft/FlatUIKit,tfrank64/FlatUIKit,hanangellove/FlatUIKit,yangchenghu/FlatUIKit,AmitaiB/FlatUIKit,hieutn/FlatUIKit,algoaccess/FlatUIKit,SummerHanada/FlatUIKit,yungfan/FlatUIKit,0x73/FlatUIKit,lioonline/FlatUIKit