Wildcard regex matching for includes

[isobelormiston]

This adds regex-based wildcard matching to the 'include' flag, so that labels can be matched more flexibly.

Unfortunately, this adds a little breaking change as matching on just * will no longer work as before. We could either add a hack to this version so that a single * at the end of the pattern matches like it did before, or we should really wait until the next major release :(

[peterebden]

I'm afraid this is too slow. This is going to recompile a regex every time this is called, which I think will happen for every label on every target that's built, at least once a run.

[isobelormiston]

Oh, that's a shame :(

[peterebden]

It's possible we could look at precompiling the regex (I guess it's the thing someone passes as a flag so there won't be many of them). That would help although I'm not certain how much it's worth trying to work through the compatibility issues you note.