Whoops. 'layer' parameter isnt passed in.
Set property containing human readable timestep information
Set overlay based on window porperty (from button)
Typo fix. png not json.
First run at URL caching.
Add support for python's 'with'. Also fix weird strptime bug
refinement of url caching
more tweaks to caching
urlretrieve impliments proper 'fallback' activity when expired
Clean up google static map request
remove resource when removing cache entry
URLCache shouldn't return an open file object
Put file extension on fetched object
Only add extension if the file doesn't already have one
Crop image so overlay doesn't show cone