Additional User-error flags

[yougsanghvi]

Hi!

Wanted to flag some easy-to-make mistakes as a relatively new stagg user that have added some additional debugging time to my code.

1. Staggregate tolerance: I didn't notice the small 0.00001 degree mismatches in my era5 land raster and the weights. While this is a deeper floating point problem flagged in another issue, it would also be nice to flag these small mismatches when a user input is needed to fix them. For eg, if there is a mismatch while running staggregate, it would be nice to get a warning saying there might be a floating point mismatch and that the user can try to pass in a "tolerance" value. Currently, the user simply gets an output with a bunch of NAs which can take a lot longer to debug since the small mismatches are such a subtle issue.
2. Mismatched raster: This is a smaller and more of a "user-problem" but I noticed that if you pass weights and climate raster which are of different resolutions, the code still runs but outputs all NAs. Similarly, if the raster grid and secondary weights is of different resolutions, all overlay weights are NA. It would be nice to simply flag a "differing resolution" error to make it easier for a less-experienced/skilled user.

Thanks!!