Added link target selectionbox to hallolink widget
Added link target selectionbox to hallolink widget

I ran into an issue of all links set by hallo being 'targetless'. The users I intend my implementation for cannot be asked to use the htmlview plugin for setting link targets, so the only (workable) solution I could come up with was to expand the hallolink widget to provide a selectionbox for choosing the desired link target.

Im fairly new to HalloJS and even n00-er to coffeescript, so excuse me if I failed to produce the exact right syntax.
If so, please correct my wrongs. I hope my (extremely minimal) contribution is perceived useful by others.
GerHobbelt/hallo,GerHobbelt/hallo