Hall A Analyzer

Ported the v1.5 VDC code to the v1.6 development branch in directory OldVDC. All THaVDC* classes have been renamed to OldVDC* to make the class names unambiguous. (Namespaces have a tendency to cause confusion if a lot of classes have identical names.)

The one difference to the original VDC code is that the database read functions have been changed to the 1.6 format readers for consistency. This allows users to work with identical databases. In this way, we test true differences between algorithms and skip any bugs due to the database conversion. Those can now be tested separately by comparing a replay with this new library under analyzer 1.6 with one done with analyzer 1.5.

The OldVDC code is compiled into a plugin library, libOldVDC.so, which can be loaded on demand. I suspect that not many people will want to use this old, obsolete code except for comparison studies.

I've done basic testing of the initialization. Comparison studies are to follow under issue #245.

Replay of GMP12 data with the old (version 1.5) VDC code gives results very close to those of the new code. The ported 1.5 version definitely works. Anything past this point would be an inadvertent bug.

Checked in with commit 7466205. Considering this done.