NimPNG Versions Save

Because of typo, last release required nim 1.16.0 which is not exists.

welcome new newString without zero initialization.

notable fixes:

• refactor: remove shallowCopy
• avoid nzCompressInit ambiguous call when included (https://github.com/jangko/nimPNG/pull/80)
• make getUnderlyingType work with type argument (https://github.com/jangko/nimPNG/pull/83)

various fixes related to nim-devel branch. e.g. remove shallowCopy usage.

fix previous release bug and add new openArray API in addition to seq[T] API

support seq[uint8] and string as input. better error handling using Result[T, E]

Fuzz tested with libFuzzer

nimPNG now compiles with --gc:arc

before internal reform