Log Message:
Update to 4.1.6:

--- 4.1.6 2011/03/10

fix problem with record_render: records were converted (character set
wise) even if no charset was given. Problem introduced in YAZ 4.1.5.

--- 4.1.5 2011/03/08

SRU: add methods for handling DADS SRU-proxy facets.

Separate OPAC record character set for ZOOM_record. yaz_record_render
allows a character set given as charset=from/opacfrom,to where 'from' is
the character set of a bibliographic record, 'opacfrom' is character set
of OPAC record and 'to' is the target character set.