Git commits in Moodle 2.8.4 by Andrew Davis

commit c49003263e8de9d7ab0ddeab037ea7d7cc470e32
Author: Andrew Davis <andrew@moodle.com>
Date:   Tue, 24 Feb 2015 15:56:05 +0800
Tag:    v2.8.4

MDL-29008 lang: reintroduced error silencing to prevent unit test failures

commit bbc7df8d5251cdfa7ec084b18dfe9e0aefdbefc6
Author: Andrew Davis <andrew@moodle.com>
Date:   Fri, 13 Feb 2015 04:40:46 +0800
Tag:    v2.8.4

MDL-49008 lang: removed preemptive deleting of old language files

commit 1ab376e86fd25ad0e39d89fd9ca21647db93950d
Author: Andrew Davis <andrew@moodle.com>
Date:   Thu, 12 Feb 2015 16:26:35 +0800
Tag:    v2.8.4

MDL-49008 lang: made lang update error reporting work

commit 2e77d5ec7b24861cd81af2e044e87c8a08d4fd8c
Author: Andrew Davis <andrew@moodle.com>
Date:   Mon, 26 Jan 2015 04:25:14 +0800
Tag:    v2.8.4

MDL-48942 mod_survey: synced security checks in view.php and graph.php

commit 0cce3ea50dbc6b96cdce09a1018eebe3e8095df0
Author: Andrew Davis <andrew@moodle.com>
Date:   Tue, 20 Jan 2015 17:06:42 +0800
Tag:    v2.8.4

MDL-48910 core_block: user_can_addto() respects applicable formats