Updates to ATInt to widen the acceptability of constants of integration.
Improvements to the display of unary minus when combined with division.
Trivial fix to healthcheck url.
Changes to connection as suggested in forum, 2013-6-22
Changes to connection as suggested in forum, 2013-6-22. (2)
Merge branch 'master' of github.com:maths/moodle-qtype_stack

Conflicts:
	stack/cas/connector.unix.class.php
Fix URL.
Trivial modifications, mostly to comments.
Fix #69. If a new PRT has been added, fail validation.
Additional test case.
Add missing setType calls to the form.
Merge branch 'master' of github.com:maths/moodle-qtype_stack
Minor edits to the docs.
Merge branch 'master' of github.com:maths/moodle-qtype_stack
Fix to issue #71:  https://github.com/maths/moodle-qtype_stack/issues/71
Code tidy.
Merge branch 'master' of github.com:maths/moodle-qtype_stack
Update the docs to reflect the imminent 3.1 release.
Update version and readme for the 3.1 release.
Whitespace fixups.