Moved Doxygen comments from source files to public headers.

Conflicts:
	include/libimobiledevice/afc.h
Corrected some doxygen comments in public lockdown.h
Correct wrong error codes in doxygen comments of public lockdown.h
Converted afc_fts_info and values to a typedef enum. Renamed afc_fts_entry_t to afc_ftsent_t.
Merged upstream changes.