fix(main): support the "bookmark-of" as well
fix(main): support the "bookmark-of" as well

The "bookmark-of" property is the one pushed for by http://indiewebcamp.com/bookmark while Micropub for some reason pushes for the use of a plain "bookmark" property instead: http://indiewebcamp.com/micropub#New_Bookmark

As the micropub properties should mirror the microformat properties we should at least support both.
voxpelli/node-format-microformat