add plist helper functions to reduce code duplication
add missing kLibUSBMuxVersion to plist messages
default to proto v1 (plist) with fallback to binary-only
usbmuxd_get_result: allow getting the plist result for newer usbmuxd commands
implement ListDevices command and use it in usbmuxd_get_device_list()
make libplist dependency/protov1 support mandatory
implemented usbmuxd_read_buid()
implemented usbmuxd_read/save/delete_pair_record()
bump soversion to reflect new interface functions
correct some debug messages
Fix checking return values from usbmuxd
make 'use_tag' usage thread safe and ignore tag mismatch errors
make usbmuxd_send() return a negative errno value like specified in the docs
removed mutex lock - concurrency issues where caused by tag mismatch