SoundEngine Fix for ofxiOS leaking memory #2745

Fix as proposed by @rraallvv #2745
Merge branch 'iOS-SoundEngine-MemoryLeakFix' of git://github.com/danoli3/openFrameworks into danoli3-iOS-SoundEngine-MemoryLeakFix
Merge branch 'danoli3-iOS-SoundEngine-MemoryLeakFix'
Merge pull request #2802 from admsyn/fix-ios-soundengine-memory

Fix iOS SoundEngine memory leak