Fix debug output for various data structures

[jbaublitz]

Would adding this feature cause a breaking change?
For some changes, yes. Others can be included in a patch release.

Is your feature request related to a problem? Please describe.
Debug output is currently very unhelpful for types like flags, buffers, etc.

Describe the solution you'd like
I would like:

• Buffer to hide the bytes it contains
• FlagBuffer to be replaced by bitflags as described in Consider using bitflags crate in place of impl_flags macro and FlagBuffer #107 (breaking change)

I would also like to add better trace logging for buffers during deserialization to help with debugging. Currently there is some buffer debugging but often, the buffers are too large to actually help much. I'd like to use a combination of TypeSize and the usize from FromBytesWithInput to display the buffer that will be parsed for that particular data structure.

This is related to #105 and may end up replacing it.