Expose little endian types

[timkurvers]

Am currently dealing with formats that deal exclusively with little endian and it'd be nifty exposing int16le, uint32le and the likes alongside its big endian cousins.

Thoughts?

[devongovett]

Sounds good. Maybe expose e.g. uint32be as well, as an alias to the current uint32, for consistency.

[timkurvers]

👍 Should these be individually tested too?

[timkurvers]

Thanks! 👍