Add unsigned 32-bit binary reads and writes

Add ReadUInt32 and WriteUInt32 methods to BinaryStream and MemoryBlock for reading and writing unsigned 32-bit integers. These methods make it easier to work with binary file formats and protocols that use values from 0 through 4,294,967,295.

Reads should produce the new UInteger32 type. Writes should accept that type and preserve all 32 bits. Both byte orders should follow the object's existing LittleEndian setting.

Existing signed integer methods should retain their current signatures and behaviour.