replaced TARGET_OF_IPHONE with TARGET_OF_IOS

ofOpenALSoundPlayer was using old TARGET_OF_IPHONE guard,
have updated to use TARGET_OF_IOS guard.
Merge branch 'master' of https://github.com/openframeworks/openFrameworks
ofxiOSKeybaord fix.

- getText now returns the UITextField text value.
- getLabelText is now deprecated as it was not properly implemented.
removed unused _ctext variable.
Merge pull request #3077 from julapy/ios_keyboard_getText_fix

ofxiOSKeyboard fix.