Aways return geographic coordinates from ee.Geometry.bounds()

[jdbcode]

Fixes #198

Aways return geographic coordinates from ee.Geometry.bounds() because the later call to pyproj.Transformer.from_crs to get coordinates in the requested crs is expecting geographic (lat lon) coordinates. If a projection argument is provided, the current implementation wrongly returns the bounds of the request in the crs of the projection, it should be in EPSG:4326, which is what happens if a person specifies crs and scale instead of projection because self.projection is never set in this case and therefore ee.Geometry.bounds() defaults to EPSG:4326, which is fine.

See #198 for a repro/testing script.