remove libusbmuxd sources and adapt source tree to use autotools

libusbmuxd has been split off and is now managed in a separate repository.
By the time of this commit, the repository is:
git clone http://git.sukimashita.com/libusbmuxd.git
silence several compiler warnings
added missing usbmuxd-proto.h
install usbmuxd to $prefix/sbin, not $prefix/bin
added preflight worker implementation to handle initial device pairing
make sure usbmuxd -x does not terminate when unpaired devices are still present
Bump version to 1.0.9
preflight: Fix some comments to comply to C89
preflight: Allow pre iOS 6 devices to become visible if pairing fails

This allows any client to react and handle pairing errors which includes
password protected devices and alike.
preflight: Add missing definition for userpref_device_record_get_host_id()
preflight: Use userpref_get_system_buid() instead of hardcoded path
preflight: Trigger new trust dialog if user denied pairing before

This changes allows to replug a device to trigger a new trust dialog if the
user did deny the pairing before.
main: enclose libimobiledevice related code in #ifdefs
preflight: handle invalid pair records properly
preflight: don't wait for trust if device is at setup screen
udev: lower rules numbering to make sure we start as early as possible

To prevent the trust dialog from appearing on iOS7 devices we need to make
sure that no PTP access is happening before usbmuxd starts. So we start as
early as possible so the device will be in trusted host state.
actually install udev rules file
utils: make FOREACH macro _iter variable unique
device: suppress two compiler warnings with appropriate casts
client: added mutex around client_list access