gnucash-docs maint: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/889b6c2d (commit)
	 via  https://github.com/Gnucash/gnucash-docs/commit/4dbf2029 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/9d532a46 (commit)



commit 889b6c2d05680aaaec28706bcd786e5a6ca17d34
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat Dec 17 10:44:46 2016 -0800

    Release 2.6.15

commit 4dbf202974210cc1b90a99792057e4395709b9d7
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat Dec 17 10:19:24 2016 -0800

    Update AUTHORS.



Summary of changes:
 AUTHORS      |  58 ++++++++---------
 ChangeLog    | 208 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 NEWS         |  16 ++++-
 configure.ac |   2 +-
 4 files changed, 253 insertions(+), 31 deletions(-)