Add non-resident attribute data run + resident Index Entries in Index Root support

[uckelman-sf]

This exposes in the Python bindings the extra support provided in https://github.com/omerbenamram/mft/pulls/118.

NB: The changes in the PR against mft are required for this to compile.

[omerbenamram]

Thanks for this! Is there any specific reason you've enabled the extension module feature of PyO3? I'd like this to stay compatible with the abi3 feature set to easier support future python version, so we won't need to maintain a wheel matrix.

[kastonework]

Thanks for this! Is there any specific reason you've enabled the extension module feature of PyO3? I'd like this to stay compatible with the abi3 feature set to easier support future python version, so we won't need to maintain a wheel matrix.

Hey! Maybe I'm missing something, but extension-module was enabled before, right?
https://github.com/omerbenamram/pymft-rs/blob/master/Cargo.toml#L15

The change in this PR makes it a default feature, so it's still included by default (same as before) but we can exclude it for running cargo test (otherwise test invocation fails due to https://pyo3.rs/v0.13.2/faq.html#i-cant-run-cargo-test-im-having-linker-issues-like-symbol-not-found-or-undefined-reference-to-_pyexc_systemerror)