Add functor instance for HtmlM
Add functor instance for HtmlM

See #54

mikehat/blaze-all,iblech/blaze-html,iblech/blaze-html,FranklinChen/blaze-markup,mikehat/blaze-all,Soostone/blaze-markup-haste,dylex/blaze-markup,Soostone/blaze-html-haste,Soostone/blaze-markup-haste,FranklinChen/blaze-markup,mikehat/blaze-all,dylex/blaze-markup