MM command handlers cast away const

[dmknutsen]

Checklist (Please check before submitting)

• [x ] I reviewed the Contributing Guide.
• [ x] I reviewed the README file to see if the feature is in the major future work.
• [x ] I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.
Several MM functions cast away const on their command buffer such that they can manipulate it internally. Buffers should be copied to a local variable prior to manipulation.

Examples include:
MM_LoadMemFromFileCmd
MM_DumpMemToFileCmd
MM_SymTblToFileCmd

Describe the solution you'd like
Audit MM and clean up.

Requester Info
Dan Knutsen
NASA Goddard