Github Flavored Markdown task lists

###GFM task lists - [x] @mentions, #refs, [links](), **formatting**, and <del>tags</del> supported; - [x] list syntax required (any unordered or ordered list supported); - [x] [ ] this is a complete item; - [ ] []this is an incomplete item [test link](#); - [ ] [ ]this is an incomplete item; - [ ] this is an incomplete item [test link](#); - [ ] this is an incomplete item [test link](#); > Github Flavored Markdown task lists