Add more interactive to connection modifiers

[ctengel]

• [ ] con add -i - i.e. prompt user for length, tracks
• [ ] con mod - i.e. interactive modification of a connection
• [x] #27
• [ ] stats - show average length per route, etc

Split from #11

[ctengel]

Auto-generate lengths? i.e. shortest = 1, anything 1-1.9x is 1, 2x is 2... etc

[ctengel]

Need autogen lengths for static map