Try to fix broken IRC message.
Add tokeniser tests for backslash-escape.
Test exceptional behaviour of TimeParser.
:lipstick:
Use tags properly.
Call ResourceSource ctor explicitly.

This ensures that the ResourceSink is set to nullptr, and thus fixes
a nasty segfault if one tries to Emit without one having been set.
Add tests for PlayerState.

Tests for PlayerPosition and, subject to refactoring, PlayerFile
may follow later.
Merge pull request #51 from UniversityRadioYork/mw-test-coverage

Test coverage and other fixes