Modify gen_build to accept keys for copying into nested directories
Initial Quick Look generator setup
Move some bundles code from index.h to query.h
Rename “index.{h,cc}” to the more appropriate “item.{h,cc}”
Use @rpath so the QL generator can load frameworks from the app bundle

@executable_path is the originally-executed program, whereas @loader_path is the program that caused the load to occur (i.e. the Quick Look generator). @rpath can be changed at link time — the QL generator specifies a value that points to the enclosing app bundle’s Frameworks directory.
Move fs_cache to plist framework
Move load_bundles to bundles framework
test