Add preferred train estimated time to menu bar

With option for showing/hiding

![screen shot 2014-12-17 at 8 16 44 pm](https://cloud.githubusercontent.com/assets/1044502/5482924/695b9534-8637-11e4-9f59-929cd40d9c3b.png)
![screen shot 2014-12-17 at 9 54 59 pm](https://cloud.githubusercontent.com/assets/1044502/5482926/6ff50e7a-8637-11e4-9e3a-59ba7f48e799.png)

Currently doesn't auto update interface when switching the option

Also not sure what these Contents.json changes are
XCode automatically staged them; can revert