When construct replaced String with PaddedString, the return type changed from bytes to unicode strings (u"..." on Python 2, "..." on Python 3).

This affects a lot of conditional checks, tests, and user code. For example box type definitions.

I've updated the code to reflect this change.

For some reason sometime between 2.8.8 and 2.8.22 the arguments for Const were flipped.

The includelength parameter was added in `2.8.11`. Also removes TellMinusSizeOf as it's now unused.

The default for CString and PascalString was previously "ascii" (from what I can tell) so I specified "ascii" for everything that did not explicitly specify an encoding.

Construct 2.10 (maybe even 2.9) no longer allows you to do e.g., `Container(foo=1)(bar=2)` as an alternative to `Container(foo=1, bar=2)` and I honestly can't blame them, it makes the code extremely annoying to read and undoubtably to parse as well.

This commit simplifies them to singular construct call under a single Container object.

This way we don't have to use BitStruct and messy embedding/nesting decisions and can directly nest the language.

This removes duplicate checks and duplicate output data.

This is by no means ideal. It would be much preferred to be embedded, but the maintainer of construct has stated there is no workaround and nesting is the only option.

This means when building boxes we must now nest the data in `data` container. This also means grabbing a fields value must now specify `.data` first, e.g., `tenc_box.data.is_encrypted`. See changes with the tests. Not ideal at all.