Parlour/Sqoop Integration

If we keep `ImportPath`, it should just be a function/method. I don't see the point of creating an object just to immediately call `path` on it.

Also, if we keep it, I agree that it should handle possibly different date fields (year/month and year/month/day/hour, for instance). (I wouldn't mind having an enum representing one of the standard datetime fields that we handle: year, month, day of month, hour of day, etc ... there's been a few places where such an enum would have been useful: the file pattern stuff, abstracting over hive partition functions, this, probably other places too)

As to whether we keep it or not: the alternative is folding this functionality into `sqoopImport`, forcing users to use `customSqoopImport` if they need something different. Whether this is good or not depends how often people need to use a different import path.

The import path is only ever consumed by the `load` method, which we control, so there is no real external pressure forcing us to use a non-standard import path. However, the user of `sqoopUpload` may still need to specify a different import path if they are using the condition parameter to load a particular time slice of data.

I personally am quite partial to the idea that users explicitly control the time slice of data they are loading. So on that basis I am in favor of keeping this functionality outside the `sqoopImport` method. What I would like to see is a method which take this info, plus an enum representing the date field we "go up to", and returns the appropriate path. And another method which takes the same info plus a DateTime object to make it easy for the user to specify particular times.