Support 3 stashcodes with implied 10m height.

There are other '10m stashcodes', but these 3 are specifically requested for the present.
New support mechanism integrates the existing 1.5m cases.
(I'm not sure where this comment is going to be appear because the GitHub interface has stopped working properly on Firefox, but ...) in the definition of `_stashcode_implied_heights` it would be nice to keep the keys in order - i.e. "m01s03i225" should appear first.

Also since `_stashcode_implied_heights` is a constant it would be better in capitals.