Merge branch 'release-v15.0' into develop
Fixed config file and log file that were committed to the repo.

Note that upgrading requires care to create a valid config file and
may require backing up `errors.log`.
Added .gitignore in application/config
Added note to README.md about log file
Fixed JS error for empty .flexslider-slide object (#7558)

Dereferencing the function mediaelementplayer() on an undefined
object caused the script to stop executing with an exception, and
it was not able to continue with code farther down.
Fixed pagination issues. (#7558)

- Fixed link elements without "data-page" attributes.
- Fixed loop index limit in browse.php helper.
- Changed too-low default records per page in ExhibitBuilder plugin.
  It's unclear how to do this the "correct" way, and getting too
  time-consuming to figure out how to change it without simply
  upping the default.
- Unwrapped code in main.js that didn't have to be wrapped in a
  jQuery() call.  In that function, also removed  usage of
  jQuery text() function, which does not always return the inner HTML
  of an element, as was expected.
Bumped version to 16.0
Merge branch 'release-v16.0'