Miranda: Add Spatter request generator

[radelja]

Adds a new request generator that generates a stream of memory requests from the same input used for the Spatter benchmark. The Spatter benchmark is currently going through a refactor, and this generator is using the refactored version to parse command-line arguments passed as model options to the corresponding SDL file (spatterbench.py). Support for this generator depends on configuring SST-Elements with the build directory of Spatter using the --with-spatter configure option, e.g., --with-spatter=$HOME/src/spatter/build_serial_gnu.

• Added Spatter generator as a sub-component to Miranda
• Added test for the Spatter generator
• Updated Miranda to load generator sub-components with INSERT_STATS flag

The refactor for the Spatter benchmark can be found here: https://github.com/JDTruj2018/spatter/tree/refactor

[sst-autotester]

Status Flag 'Pre-Test Inspection' - - This Pull Request Requires Inspection... The code must be inspected by a member of the Team before Testing/Merging
NO INSPECTION HAS BEEN PERFORMED ON THIS PULL REQUEST! - This PR must be inspected by setting label 'AT: PRE-TEST INSPECTED'.