More filters on datacheck.php

[jteresco]

There's a lot in the datacheck tables. It would be helpful to be able to sort/filter by error type in addition to the existing filters by system and region.

[michihdeu]

@jteresco the existing filters by system and region are only via the url. And the error types can also be filterered this way e.g. https://travelmapping.net/devel/datacheck.php?rg=CA&show=SHARP_ANGLE