Capture FieldOutOfBound errors on drifters and Argo floats

[erikvansebille]

When a drifter (or Argo) leaves the downloaded domain, this now throws a FieldOutOfBounds error that will stop the entire virtualship run. It would be better to try/except these errors, throw a warning and then at least continue.

[j-atkins]

Current state: out of bounds errors no longer a problem for drifters (as of #264) but could in theory still affect Argo floats. TODO: look into incorporating try/except.