Several bugfixes for 0.9.12.1 release

[sserita]

This PR has a variety of small bugfixes intended for the 0.9.12.1 release, including:

• Better static DataSet error messages to address Dataset Merging Bug #340
• Allow LGST to work with TP-parameterized models for LGST doesn't work with TP-parameterized target models #366
• An optional flag to not include delay operations (and therefore emit canonical QASM2) in QASM conversion for OpenQASM returned by convert_to_openqasm includes opaque gates. #377
• Better error messages for non-TP gauge transformations for Gauge transformations on SPAM #378
• Removing the spurious file noted in Unexpected file in test_packages #381
• Fixing a ForwardSim param dimensions tuple bug
• A MarginalizedPOVM basis attribute issue reported internally

[coreyostrove]

All of these changes look good to me, great work!