Fixed another quirk with IERail API, Added documentation for train movements, increased test coverage, type object attributes.

Several issues fixed in this pull-request:

* Added documentation for train_movements
* Fixed a broken call in the documentation
* Added in a fix for another quirk with the IE Rail API:
    * When returning station data, there is a value 'Late', which logically represents the number of minutes the train is late. This isn't alway the case.
    * It actually represents the trains deviation from the scheduled arrival time, be it early or late.
* Made object attributes more type apparent, i.e. if it's an int, make it an int, likewise for dates and times.