Setting this option on projects with lots of files can reduce compilation time. Case-insensitivty requires normalization of file paths, which involves executing regex's. This shows up in the hot path of compilation profiling.

Co-authored-by: John Reilly <johnny_reilly@hotmail.com>

* Add a cache to file path mapping
This greatly reduces the time needed to resolve FilePathKey objects on watch builds.

* Address PR comments

* Bump package.json and CHANGELOG.md

Co-authored-by: John Reilly <johnny_reilly@hotmail.com>

* chore(deps): upgrade most production deps
adjusted chalk import/initialization to new major

* refactor: use namespace import

* chore: bump patch version; update changelog

* docs: add contributor name

* Add afterDeclarations to getCustomTransformers in README.md

* Emit d.ts file in subsequent runs in watch mode

* Update package.json and changelog.md

* Add afterDeclarations to getCustomTransformers in README.md

* Emit d.ts file in subsequent runs in watch mode

* Update package.json and changelog.md

* Re-fixed missing errors in watch mode

* Correct merge error

Co-authored-by: John Reilly <johnny_reilly@hotmail.com>

* Optimize fileExists callback path
Instead of looking up filePathKey twice, cache in in the local scope. This isn't a hugely expensive lookup path, but is a hot path on large project recompiles (especially after caches are blown away). Profiling shows that even the Map lookup shows non-trivial cache lookup aggregate time

* Update Changelog & package.json