Refactor pipelining

[billschereriii]

Description

The client pipelining uses CommandLists and vectors<Command*> in parallel, which is redundant in storage. This should be refactored to eliminate the redundancy

Justification

This will improve maintainability of the codebase

Implementation Strategy

One strategy might be to rework the CommandList class to store command data as a vector<command*> internally that we can access for pipelining calls