Added a DEBUG_MEM define to disable optimization and for future enhcement.
Prevented "counting" vars from being cached.
Prevented vars from being cached unless they are marked "available" in phase.
Now use var->value as the cache hash key as a unique value.
Fixed which pools we are using for rule processing.
Updated regression tests for tfns.
Updated regression test script to handle extra APR_POOL_DEBUG output.
See #364.