add PLIST_OPT_NONE

[tihmstar]

Add enum val for when no extra functionality is needed. When trying to write plist to file using the function:

plist_write_to_file(p_someplist, somefilename, PLIST_FORMAT_XML, 0)

The C++ compiler will complain that 0 (int) is not a valid plist_write_options_t. Instead it should be written as something like this:

plist_write_to_file(p_someplist, somefilename, PLIST_FORMAT_XML, PLIST_OPT_NONE)

[nikias]

who actually uses a C++ compiler...

[nikias]

61f01b1b06ff906cce4c4c3b2aa031f2efaf1201