Bump version to 2.6.0

Reuse stack-allocated Vec reading chunk

This avoids building a new Vec chunk on each iteration

Convert range test to guard

Perform large Vec reads in chunks

This avoids trying to pre-allocate too large of a Vec
if the amount of bytes requested is much larger
than the number of bytes in the input stream.

Provide default implementations for new const-based methods

Ensure signed reads/writes have at least 1 bit for sign

This would cause underflow panics before, but should now
generate proper errors at runtime or compile-time.

Add rust-version field to Cargo.toml

Remove some outdated README info

Bump version to 2.3.0

Bump version to 2.2.0