As for the identification and relocation of file resources by hashsums
and file properties, everything has been implemented in the master
branch already (resources framework, see include/*Resource*.h
src/core/*Resource*.cpp and src/gui/*Resource*.cpp) (and even is used
by AudioFileProcessor, Sf2Player and so on). Before reinventing the
wheel, we should backport this resource framework to a separate
working branch based on the current stable branch.