Add Journey model and update RecordFragment to use it

It compiles and everything seems to work still. No idea whether any of the `Parcelable` stuff actually works.
For reference, joda-time has an `ISODateTimeFormat` class:

<http://www.joda.org/joda-time/apidocs/index.html?org/joda/time/format/ISODateTimeFormat.html>

*I'm not saying we should use it, I'm just trying to compare libraries.*