Use LMDB Driver by default
Add several more caching levels for -MOFast
v2.020004

 [Dependencies::Stats]
 - Dependencies changed since 2.020003, see misc/*.deps* for details
 - develop: ↑4
 - runtime: ↑8 (recommends: +2 -2)
 - test: ↑1 (recommends: ↑1)

 [Utils]
 - dep_changes.pl : Use LMDB driver by default
 - dep_changes.pl : Add several more levels of advanced caching for blazing fast performance.
post-release cleanup