MDL-41593 admin: use default setting if preventexecpath active

This resolves problems when installing Moodle
and addons when preventexecpath active.

Please note the admin_setting_configfile is still
incorrectly restricted - this will be resolved by
MDL-40949.
MDL-47728 tool_monitor: added capability check before displaying link
MDL-47400 gradereport_history: Fix string notempty test for Oracle
Merge branch 'MDL-47400-master-2' of git://github.com/andrewnicols/moodle
Merge branch 'MDL-47728_master' of git://github.com/markn86/moodle
Merge branch 'wip_MDL-41593_m28_preventexecdefault' of https://github.com/skodak/moodle
MDL-47736 editor_atto: exclude <br> from being restored
Merge branch 'MDL-47736_master_fix' of git://github.com/markn86/moodle
MDL-47736 editor_atto: added fix for IE 9 and 10
Merge branch 'MDL-47736_master_fix2' of git://github.com/markn86/moodle
MDL-46527 grades: grade_get_grades external function rewritten
Merge branch 'MDL-46527-master' of git://github.com/jleyva/moodle
MDL-46527 Grades: Webservice only returns first activity grade.