Support Controlled gates properly on PyQVM

[dwillmer]

Description

Fixes #1259

Controlled gates weren't getting treated properly in the QUANTUM_GATES / matrix globals. The name needs to be modified to pick up the right matrix. As a result I've added a new modified_name property which corrects the name for controlled gates, and a unit-test showing that the example in 1259 now passes.

Checklist

• The above description motivates these changes.
• There is a unit test that covers these changes.
• All new and existing tests pass locally and on Travis CI.
• Parameters and return values have type hints with PEP 484 syntax.
• Functions and classes have useful Sphinx-style docstrings.
• All code follows Black style and obeys flake8 conventions.
• (New Feature) The docs have been updated accordingly.
• (Bugfix) The associated issue is referenced above using auto-close keywords.
• The changelog is updated, including author and PR number (@username, gh-xxx).

[ameyer-rigetti]

@dwillmer Thanks for the contribution!

You might consider cherry-picking this to the rc branch so that this can come with pyquil v3, then updating this PR to go into rc. After the v3 release, we'll do all work on the rc branch and publish release candidates after each merged PR.

[dwillmer]

Howdy, thanks @ameyer-rigetti - have re-pointed to rc as you suggested, no conflicts with base so have left it as-is (there's only 3 existing lines changing, the rest are all new, so not surprising.)

[ameyer-rigetti]

Howdy, thanks @ameyer-rigetti - have re-pointed to rc as you suggested, no conflicts with base so have left it as-is (there's only 3 existing lines changing, the rest are all new, so not surprising.)

Great @dwillmer, thanks! Once the remaining checkboxes are ticked, we can review/merge.

[ameyer-rigetti]

Hi @dwillmer, just following up on this. Are you still interested in seeing this through?