delta: concatenate multiple delta flags when listed with comma as separator
main-no-init: restructure --version, --help and --dump-configuration-items handling
main: don't broadcast reload event on the bus
uselessfs: remove uselessfs

The idea of a FUSE overlay proved to be impractical in our rudimentary case,
as such we are sticking to simple flat files and locking.
build-sys: rid of FUSE references
install: indentation
control-request: add generic job start
control-response-util: proper types for unit enable operations
manager: make fifo_control_loop() part of manager_loop()
control-request: add stubs for is-active and is-failed
manager: move FIFO loop below epoll event loop
manager: restart FIFO loop upon SIGUSR1, don't init bus by default
path: unlink bus callbacks
scope: unlink bus callbacks
service: unlink bus callbacks
slice: unlink bus callbacks
snapshot: unlink bus callbacks
socket: unlink bus callbacks
target: unlink bus callbacks
service: bus callback remnants