All other ranges and slicing uses exclusive end so i think it make sense
to make it consistent.
Update docs and add additional example for non-byte-aligned field.
Also fixes issue showing zero bit ranges as start-NA.
Basic support, can also do CER and DER but without any extra validation.
No schema support.
Redo format doc.md usage a bit, now format/<dir>/<format>.md instead.
Related to #20
