Delvewheel

- Restore the load order calculation because it turns out to be necessary for improving support for delay-load DLLs.
- Improve support for delay-load DLLs.

- Clarify the supported platforms in the README.
- Improve comments and docstrings.
- Remove load order calculation. The `.load-order` file still exists to aid in loading DLLs for Python 3.7 or lower, but it no longer contains the DLLs in any particular order.
- Preserve line endings when patching `__init__.py`.
- Remove attribute certificate table when name-mangling. This also removes the Visual C++ redistributable DLLs from the no-mangle list. They will now be name-mangled by default.

- Fix the calculation for the `SizeOfImage` and `SizeOfInitializedData` PE headers during name-mangling.
- During name-mangling, if enough internal padding space exists within a DLL, use this space to write the new dependency names instead of creating a new PE section. This allows us to name-mangle the dependencies of a DLL containing trailing data as long as enough padding space exists.
- Remove `libwinpthread` from the default no-mangle list.

- Improve error message if `--strip` fails to remove all trailing data.
- Correct the calculation that determines whether a DLL contains trailing data if the last entry in the PE section header does not correspond to the last section of the PE file.
- Remove the `machomachomangler` dependency. `delvewheel` now takes full responsibility for DLL name-mangling.

- Use Unix line endings for the `RECORD` and `DELVEWHEEL` metadata files.
- Improve error message in name-mangling step when a DLL has trailing data.
- Preserve the order of paths specified with `--add-path`.
- Introduce the `--strip` flag to automatically strip DLLs with trailing data during the name-mangling step.

- Drop support for Python 3.6. Python 3.7+ will be required to run `delvewheel` itself. Wheels with a target Python version of 3.6 can still be repaired.
- Don't vendor DLLs included with CPython 3.9 or 3.10 arm64 for wheels targeting those versions.
- Make the `DELVEWHEEL` metadata file more structured.
- Add tests for wheels that have no external DLL dependencies.
- Include `delvewheel` version in help menu.