Update BUILD instructions to be a bit more current.
Changes to be able to build with/without Shared Dasd support:

Make changes necessary to successfully build without OPTION_SHARED_DEVICES defined.
Define new HQA Build Scenarios 12 & 13 for building with/without OPTION_SHARED_DEVICES.
Merge branch 'master' of github.com:hercules-390/hyperion

Conflicts:
	BUILDING
More BUILDING and INSTALL tweaks.