Bike-rack parametric

Based on the wonderful design of
http://www.thingiverse.com/thing:211495

Bike-rack parametric. You can change the variable "aantal_fietsen" and the rack will automatically get wider or smaller. Up to 1 bike.

The text however should be changed by hand.
Will think about a way to change fontsize and center the text according to the size of the bike-rack.