Initial tested release

Fully functional core complete. User-tested in MSVC, CI build for Linux. Many additional improvements/refinements possible. Items for review and posible future work prior to v1.0 release:

• Additional static utility methods for PooledObject.
• Expansion or option for variable-sized object pools.
• Tests and documentation for stand-alone (i.e. not type-integrated) object pools.
• Performance testing.