v2.2 patch notes

[dgasmith]

Gathering thoughts on the 2.1 patches notes and remaining TODO's.

Remaining items:

• Unicode support for Python 2.7 Support for get_symbol(116) in Python 2 #42.
• Update changelog before releasing.
• Docs passing updating doc strings to always contain a small example.

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New features:

• (Make get_symbol(large_number) work in Python2 #48) Intermediates can now be shared between contractions, see here for more details.
• (make shared_intermediates thread-safe #53) Intermediate caching is thread safe.

Enhancements:

• (Make get_symbol(large_number) work in Python2 #48) Expressions are now mapped to non-unicode index set so that unicode input is support for all backends.
• (allow sharing for tensorflow and theano as numpy backends #58) Adds tensorflow and theano with shared intermediates.

Bug fixes:

• (Rename symbols to support torch.einsum #41) PyTorch indices are mapped back to a small a-z subset valid for PyTorch's einsum implementation.

[dgasmith]

I need to do a small docs cleanup, but I think we are ready for v2.2. @jcmgray @fritzo any further changes that need to be made?

[fritzo]

I have no pending changes. Looking forward to this release!

[dgasmith]

Planning to mint 2.2 tonight unless there are any blockers?

[jcmgray]

The fix for #50 should just be a few lines, so I might throw a test together now and see if it's working. Not a crucial addition however, so press ahead if you want.

[dgasmith]

Up to you, I am happy to wait a few more days if you are close to a fix for #50.

[jcmgray]

I've put something together in #58, it was slightly more involved than I expected so if you or @fritzo have any comments it can always wait!

[dgasmith]

v2.2 is now on PyPI and conda-forge is currently building (~30 minutes until deploy).

Let me know if these distributions give you any issue.

[dgasmith]

No problems with the distributions reported. Closing.