master updated (70341cab3e -> 90ec9bb83e)

[Sam Steingold]

sds pushed a change to branch master.

      from  70341cab3e string-equal-ignore-case: new function
       new  1e3a7bf69d avoid error when message-fetch-field returns nil
       new  90ec9bb83e restore and obsolete `gnus-string-equal' and 
`bibtex-string='


Summary of changes:
 lisp/gnus/gnus-art.el    |  4 ++--
 lisp/gnus/gnus-util.el   | 10 ++++++++++
 lisp/textmodes/bibtex.el |  5 +++++
 3 files changed, 17 insertions(+), 2 deletions(-)