Git commits in Moodle 2.8.4 by Eric Merrill

commit fb50700b4e6fba1556bfa62e155eaf562af284c4
Author: Eric Merrill <merrill@oakland.edu>
Date:   Fri, 27 Feb 2015 08:46:37 +0800
Tag:    v2.8.4

MDL-47911 gradebook: Improve the performance of set_usedinaggregation

commit 3272e14576a9239e8743d19e45adaa74492d5ce2
Author: Eric Merrill <merrill@oakland.edu>
Date:   Wed, 25 Feb 2015 04:18:15 +0800
Tag:    v2.8.4

MDL-47000 session: Update memcached version referecnes to 2.2.0

commit 181269bf32413b8ba147dc073b8a14333a9f458f
Author: Eric Merrill <merrill@oakland.edu>
Date:   Wed, 25 Feb 2015 03:53:02 +0800
Tag:    v2.8.4

MDL-49285 quiz: Include lib.php for phpunit test

commit 68adf314ecf625301243d466969776f7543ceb4a
Author: Eric Merrill <merrill@oakland.edu>
Date:   Fri, 13 Feb 2015 06:07:15 +0800
Tag:    v2.8.4

MDL-48993 gradebook: When importing new items, treat blank or - as empty

commit 49f1acf17419facd621894aeeac3d4d0eb186ec3
Author: Eric Merrill <merrill@oakland.edu>
Date:   Fri, 13 Feb 2015 05:15:23 +0800
Tag:    v2.8.4

MDL-48991 gradebook: Fix style problems

commit fc63b8cf816bbb90a2b63ac91575e80c02fa1fcf
Author: Eric Merrill <merrill@oakland.edu>
Date:   Wed, 11 Feb 2015 05:19:09 +0800
Tag:    v2.8.4

MDL-49160 quiz: Make sure to not select an outcome grade item