Add strict varuint and pointer parsing #56

Job	Run time
Features (--all-features)	56s
MSRV (1.88)	34s
Test (macos-latest)	4m 33s
Test (windows-latest)	8m 16s
Isolated no-default-features	24s
Clippy	1m 6s
Rustfmt	7s
Test (ubuntu-latest)	4m 36s
Features (--no-default-features)	53s
Docs	1m 2s
	22m 27s

Provide feedback