Support MIDI in OpenAL backend.
`$DEFAULT_SOUNDFONT` must be set.
Set ICU library path in cmake.
Merge pull request #308 from take-cheeze/al_midi

Support MIDI in OpenAL backend.
Merge pull request #313 from Zegeri/development

Improve inns and fix some bugs
Tests: Get proper directory separator from detected encoding before calling filefinder
Merge pull request #316 from fdelapena/master

Tests: Get proper directory separator from detected encoding before call...
Fix #317.
Merge pull request #318 from take-cheeze/fix_317

Fix #317.
Fix events blocked by messages