function min_rail_width renamed to min_max_rail_width

Re #149

@karavanjo can you take a look at m4a.routes.js change? it looks like we have a global var there which can take its value from the previous iteration of
```javascript
$.each(profileBarriersIndicators.visible, function (index, indicatorName) {
```
but i'm not sure which value to set to initially: 
* false will make a station not available 
* true will add ```invalid``` class