memory leaks from generate

[cwsmith]

For a large parallel mesh generation case valgrind memcheck reports that all processes are leaking the same amount of data:

==1542614== LEAK SUMMARY:
==1542614==    definitely lost: 235,866 bytes in 1,523 blocks
==1542614==    indirectly lost: 262,406 bytes in 2,876 blocks
==1542614==      possibly lost: 71,744 bytes in 163 blocks
==1542614==    still reachable: 23,371,512 bytes in 19,065 blocks
==1542614==         suppressed: 0 bytes in 0 blocks

At first glance there appear to be a handful of SimModSuite objects that are not being freed properly; likely a mistake on our end. I'm looking into this now.

Running a smaller serial case has similar leaks:

==1547663== LEAK SUMMARY:
==1547663==    definitely lost: 234,030 bytes in 1,491 blocks
==1547663==    indirectly lost: 255,212 bytes in 2,803 blocks
==1547663==      possibly lost: 71,744 bytes in 163 blocks
==1547663==    still reachable: 23,840,074 bytes in 23,208 blocks
==1547663==         suppressed: 0 bytes in 0 blocks
==1547663== Reachable blocks (those to which a pointer was found) are not shown.
==1547663== To see them, rerun with: --leak-check=full --show-leak-kinds=all

some additional discussion is here: #397