Compare changes

The overall goal here is to get 1. better support for doing comparisons over large galleries (in terms of memory management), and 2. multi-process comparison support (for handling distances that are not thread-safe)

 Changes include:
Modifying compare to use the Transform hierarchy (so that we can leverage ProcessWrapper, and Stream)

Distancing incremental gallery reading, and incremental output from Globals->blockSize (these things can now be set on a per object basis).

Memory management changes in compare: only keep the smaller gallery being compared in memory, incrementally read templates from the larger gallery (enrolling in-line as needed), and comparing them against the fixed gallery, incremental output consistent with this strategy (incremental output was already possible via mtxOutput, but now we can structure this in terms of rows/cols instead of square blocks).

Multi-process support: calling br with "-multiProcess true"  causes AlgorithmCore to attach ProcessWrapper transforms to the algorithms used in -enroll and -compare commands.