Inflexible Bracket remix

Remix of http://www.thingiverse.com/thing:654128

For some reason, my printer refused to the print the original saying that the STL wasn't valid - imported into sketchup and re-exported and seems to be ok.

Also, added a two bracket version...

N/B: Didn't draw anything... I merely imported and exported the bracket by Norwegian1, so I claim no credit whatsoever for this.