TimePicker widget for Leanback

A spinner type VerticalGridView based picker widget for displaying time
according to the current system locale. The picker can be customized to
work in 2 modes based on xml attribute: 24-hour and 12-hour mode.
In 12-hour mode, AM/PM will be displayed next to the selected time.

Bug: 33751452
Test: ./gradlew support-leanback-v17:connectedCheck
-Pandroid.testInstrumentationRunnerArguments.class=android.support.v17.leanback.widget.TimePickerTest

Change-Id: I220d9b7e0183c5938cf04d1c751179397ae554fa
11 files changed