Merge branch 'master' of github.com:maths/moodle-qtype_stack into wipcasblocks

Conflicts:
	doc/en/Developer/Development_history.md
Merge branch 'wipcasblocks' of github.com:maths/moodle-qtype_stack into wipcasblocks

Conflicts:
	doc/en/Developer/Development_history.md
Mapping the old stack_cas_text_test::test_get_all_raw_casstrings to the new blocks.
Tests for conditionalcasstrings.
Merge pull request #105 from aharjula/wipcasblocks

Wipcasblocks: stack_cas_text_test::test_get_all_raw_casstrings