Implement the Allocator trait from the unstable allocator_api

[rmja]

No description provided.

[adamgreig]

Thanks for the PR! I'll check over the Allocator part in more detail later, but in the meantime, could you change the rust-toolchain file to the newer rust-toolchain.toml format please? Details are here.

[rmja]

@adamgreig I changed the format.

[jannic]

Would that mean that CI needs to revert to nightly, undoing #66?

[adamgreig]

The rust-toolchain file is from before we swapped to stable, so I think it would suffice to just add a new test case to the CI that uses nightly and enables the new feature, but still generally build and test everything else on stable.

[rmja]

@adamgreig is there something I can do to make some progress on getting this merged? :-)

[rmja]

@adamgreig I added the allocator_api feature as part of CI. Let me know if there is anything more here that I can do.

[newAM]

Thanks for the pull-request!

I'll try to get a release out today / tomorrow.