Fixes # .

Summary/Motivation:

Working with templatization and standard form (through the new contrib.solver gurobi_direct interface), we found several bugs:

• standard_form was not correctly eliminating fixed variables from the columns array and A and c matricies
• templatizing scalar objectives was storing the template information in an invalid attribute

Changes proposed in this PR:

• remove fixed vars from the A and c matricies before returning from standard_form
• fix a bug where scalar objectives stored the template info in the wrong place
• remove some unneeded redundant code
• add test of generating standard form with fixed variables

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.