Fix warnings: DeprecationWarning and prints use warnings.warn.

[irm-codebase]

Small PR with some fixes:

• print messages in disaggregate.py now use python's warn so stderr catches them.
• DeprecationWarning was a "dead" case due to the use of raise, later code was unreachable. It is now a warning of the correct type, so the code continues, implementing the fix after the warning.
• added **/tmp/* to .gitignore so test code files do not show up in git.

[irm-codebase]

@jnnr: I experienced some issues when testing locally. The test_performance_disaggregate_to_raster would not finish. Perhaps I did not set something correctly on my side?

The change should be benign, it does not touch core logic.

[jnnr]

Thanks for pointing to this, @irm-codebase! I agree with the warning. The print statements are rather informational and not warnings, so I rather convert them to logger.info. I take this with other pre-release clean-ups here #25. Let me know if you have objections.