fixes bug (error) when not passing url to preProcess or prepInputs call

[tati-micheletti]

mainly just inverted two lines and added a NULL to guessed file when url is not passed.

[achubaty]

url = NULL is not the same as the url being unreachable (if user is offline). To me it looks like the only change needed is line 477 where basename(url) is called. It just needs to handle the url = NULL case.

Your changes result in a NULL file being guessed at even when url is provided but not reachable.

[tati-micheletti]

Hey Alex, I am not sure this would work. Now that I checked it again, the problem is that when url = NULL, grepl("drive.google.com", url) returns logical(0), which in turn, makes the if statement fail. That's why I first test to see if there is an url provided, and if thats TRUE, it tries to guess the file name. I think that the problem is that I thought that url.exists() was to check if the user provided a url... I fixed it now. Will test it right after lunch!

[coveralls]

Coverage decreased (-0.004%) to 78.165% when pulling 55d5a19 on tati-micheletti:development into dded345 on PredictiveEcology:development.