* make Buf and BufMut usable as trait objects
- All the `get_*` and `put_*` methods that take `T: ByteOrder` have
a `where Self: Sized` bound added, so that they are only usable from
sized types. It was impossible to make `Buf` or `BufMut` into trait
objects before, so this change doesn't break anyone.
- Add `get_n_be`/`get_n_le`/`put_n_be`/`put_n_le` methods that can be
used on trait objects.
- Deprecate the export of `ByteOrder` and methods generic on it.
* remove deprecated ByteOrder methods
Removes the `_be` suffix from all methods, implying that the default
people should use is network endian.
This commit is a significant overhaul of the library in an effort to head
towards a stable API. The rope implementation as well as a number of buffer
implementations have been removed from the library and will live at
https://github.com/carllerche/bytes-more while they incubate.
**Bytes / BytesMut**
`Bytes` is now an atomic ref counted byte slice. As it is contigous, it offers
a richer API than before.
`BytesMut` is a mutable variant. It is safe by ensuring that it is the only
handle to a given byte slice.
**AppendBuf -> ByteBuf**
`AppendBuf` has been replaced by `ByteBuf`. The API is not identical, but is
close enough to be considered a suitable replacement.
**Removed types**
The following types have been removed in favor of living in bytes-more
* RingBuf
* BlockBuf
* `Bytes` as a rope implementation
* ReadExt
* WriteExt
