Remove code that has no remaining user

Three declarations had no definition and the rest had no user left.

src/Makefile.am

@@ -17,7 +17,6 @@ libsub_root_a_SOURCES = \
 	core/http_queue.h \
 	core/manager.cc \
 	core/manager.h \
-	core/range_map.h \
 	core/view.cc \
 	core/view.h \
 	core/view_manager.cc \
@@ -171,7 +170,6 @@ libsub_root_a_SOURCES = \
 	utils/functional.h \
 	utils/gzip.cc \
 	utils/gzip.h \
-	utils/list_focus.h \
 	utils/lockfile.cc \
 	utils/lockfile.h \
 	utils/waitpid_queue.cc \