Add keyLabelAlign attribute to Keyboard XML

java/res/values/attrs.xml

java/res/values/strings.xml

java/res/xml-xlarge/kbd_phone.xml

java/res/xml-xlarge/kbd_phone_symbols.xml

java/res/xml-xlarge/kbd_qwerty_row1.xml

java/res/xml-xlarge/kbd_qwerty_row2.xml

java/res/xml-xlarge/kbd_qwerty_row3.xml

java/res/xml-xlarge/kbd_symbols.xml

java/res/xml-xlarge/kbd_symbols_shift.xml

java/src/com/android/inputmethod/latin/BaseKeyboard.java

java/src/com/android/inputmethod/latin/BaseKeyboardView.java