Refactoring keyboard drawing code and KeyDetector

java/src/com/android/inputmethod/keyboard/KeyDetector.java

java/src/com/android/inputmethod/keyboard/KeyboardView.java

...android/inputmethod/keyboard/MiniKeyboardKeyDetector.java

.../src/com/android/inputmethod/keyboard/PointerTracker.java

...om/android/inputmethod/keyboard/ProximityKeyDetector.java

tests/src/com/android/inputmethod/latin/SuggestHelper.java