This moves the class CBlockFileInfo from main.h to the BlocksDB_p.h
file as that is the class where it is mostly used.
There is a global variable in main.{h|cpp} left but since that is
strictly limited to main.cpp it made no sense to details slip out
via the massively overused main.h
These are technically static libs, but not in any way shared libs.
They are used solely only by this repo and really only by the hub.
Most important, no header files are installed and basically none of
the normal rules for reusable libraries are applied to these files.
tomFlowee