The original implementations of the reader and writer didn't properly

handle multi-byte encodings, such as UTF-16 or UTF-32 strings.
The reason for this came down to newlines. We were looking for and

adding newlines based on their 8-bit representation, assuming that all

content would end in those, or that we could add them to the end of each

line while splitting. This didn't actually work, and would result in

failures in multi-byte encodings.
A few things had to be done to address this:


Some design flaws in the text utilities, which made assumptions on

   lengths, offsets, and the presence of newline characters, had to be

   fixed.


We no longer store our newline constants as byte strings, but rather

   Unicode strings. They're then encoded as needed to ensure that

   they're in a compatible format. BOMs are stripped from these, to

   avoid further corruption of content.


The order in which we encode, decode, and process strings for content

   sections has changed a bit. We add on a missing newline before

   encoding, rather than after. We encode or decode newlines at the same

   time as the content strings.


Unit tests were updated to check different multi-byte encodings for all

the content sections, making sure they are written and parsed correctly.

All unit tests pass on Python 2 and 3.