Recents clear all app lock option.
Apps can be locked and unlocked from being clearable in
the recents panel by selecting the option in the popup
menu when long pressing the item. by 0xD34D

PS2:
Remove commented out line and add method descriptions.

PS3:
Persist locked tasks.

PS4:
Use persistentTaskId.

PS5:
Fix landscape layout

Conflicts:
	packages/SystemUI/res/menu/recent_popup_menu.xml
	packages/SystemUI/res/values/dokdo_strings.xml
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java