This change introduces Rust implementations of two functions related to
pattern handling, all located in match.py:
These utils are useful in the long-term effort to improve hg status's
performance using Rust. Experimental work done by Valentin Gatien-Baron
shows very promising improvements, but is too different from the current
Mercurial core code structure to be used "as-is".
This is the first - albeit very small - step towards the code revamp
needed down the line.
Two dependencies were added: regex and lazy_static. Both of them
will be useful for a majority of the Rust code that will be written,
are well known and maintained either by the Rust core team, or by
very frequent contributors.