distcheck still doesn't succeed - there are a bunch of test files that don't
get cleaned up. moving on, but will make a ticket for it.

some TODOs still - see "___" placeholders.

Merging Xu's multi-application workload with MPI Sim layer, enabling time-stepped series data output for the MPI traces (single and multiple applications), updating documentation

Moving computation calls at MPI-Sim LP finalize, so that if the application (e.g. lulesh) doesn't have a call to finalize then the communication times don't mess up