[#21] Update release information

Merge branch 'COMP23311/EX3/slashaction_test_coverage'

[#20] Tidied up tests in regards to code review

[#20] Updated SlashActionRepositoryTest in regards to code review

[#19] Change tests in accordance with the new implementation

[#19] Group actions into relevant subsets

[#19] Add Stendhal header to test classes we wrote

[#19] Migrate AwayAction to XML

[#19] Change use of remainder for actions to check for empty remainder

[#19] Write VolumeActionTest class

[#19] Wrote ClientAction test

[#19] Wrote HelpAction test

[#19] Write GMHelpActionTest

[#19] Delete TeleportAction and InvisibleAction

[#19] Altered SlashActionRepository to test DefaultAction, fixed typos