call.c (add_function_candidate): Set LOOKUP_COPY_PARM for any constructor called with a single argument that...

	* call.c (add_function_candidate): Set LOOKUP_COPY_PARM for any
	constructor called with a single argument that takes a reference
	to the constructor's class.
	(BAD_CONVERSION_RANK): New.
	(compare_ics): Use it to compare bad ICSes.

From-SVN: r161443