Experiences from testing

Theories prepared for testing
There are three theories prepared for such comparisons:
 * 1) Test_Isac.thy: runs all tests, which requires about 3 min. as with 2018. Requires session Isac. Is run by ./zcoding_to_test.sh, Policies_for_the_test_suite.
 * 2) Test_Some.thy: Requires session Isac.
 * 3) Text_Theory.thy

Compare behaviour of tests before / after code update
Comparing is done with meld.