Replace () with (void) in function prototypes

() and (void) are 2 different things in C, and can cause gcc warnings:

error: function declaration isn't a prototype [-Werror=strict-prototypes]
 idevice_error_t idevice_event_unsubscribe();

This commit replaces () with (void) in installed headers.
Merge branch 'libimobiledevice-master'
Replace () with (void) in libinternalcommon and tools for consistency
cython: Add DebugServerClient class to communicate with debugserver
cython: Add get_path_for_bundle_identifier() method to InstallationProxyClient
debugserver: Remove const argv requirement for creating commands
idevicedebug: Fix memory leak and compiler warnings regarding command creation
debugserver: Return enum error type instead of int for type consistency
lockdown: Add new LOCKDOWN_E_SERVICE_LIMIT error to detect service limit states
Improve maintainability and Requires of pkg-config file slightly
Merge remote-tracking branch 'upstream/master'