(documentation) Mention similar/alternative OSS solutions in README, plus a bit about their pros & cons

[GerHobbelt]

Mention similar/alternative OSS solutions, plus a short description & cons of using those.

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Was looking myself for a fundamental 'resource compiler' like yours. Already had inspected a few of the others and wasn't satisfied. Kept looking, found yours, which I've to test further, but it looks promising. 👍

Augmented the README at the end.