Settings : Update gesture preference check

Move the gesture outside the stylus dependency check and remove the
preference category if no children are found

Change-Id: I05ecf71dc84f5244200e3030b5ee524944339145
(cherry picked from commit f6a43a4bc50f6fba64f55c08adff16f8bdcb1c44)

Conflicts:
	src/com/android/settings/inputmethod/InputMethodAndLanguageSettings.java