Track and summarize memory usage statistics

[ChristopherHogan]

Created from JIRA HERM-45

It would be nice to be able to examine the high-water mark of each memory arena at the end of the run. For example, if a user gives %20 of Hermes memory to the transient arena, but finds that only half of that was ever used, while the RAM buffers were completely full, he or she could decrease the transient arena size by %10 and increase the RAM buffer size. This provides a way to tune applications.