More fixes and improvements as follows:

 * Use gradient when coloring node border by node state
 * Color outgoing links, not incoming ones
 * Order graph only once in the beginning (from breakconditions.js)
 * Show a message when searching for a non-existant node id
 * Fix bug in break condition aggregation where the aggreagtion
   would lock up signal collect
Merge branch 'master' of github.com:uzh/signal-collect