Git commits in Moodle 2.5.0 by Matt Petro

commit f5f36584801fb6873530ebd23f0d8b5734aae703
Author: Matt Petro <petro@engr.wisc.edu>
Date:   Tue, 16 Apr 2013 19:19:23 +0800
Tag:    v2.5.0-rc1

MDL-34403 mod quiz: fix error during enrolment

commit a538cf839e5fa1a205facdb97dc2364be474d010
Author: Matt Petro <petro@engr.wisc.edu>
Date:   Fri, 02 Nov 2012 23:07:02 +0800
Tag:    v2.5.0-beta

MDL-36025 qtype calculated: Fix handling of "-0"