Fix bug 3047653 - Text select handles stick around when they shouldn't

Text select handles will now fade out on their own after a few seconds
since many apps expect a selection to be persistent while a text field
stays focused in touch mode. The user may tap within the selection to
bring the anchors back.

Text select handles will also disappear upon leaving touch mode.

Fix a bug that impaired cut/paste from the context menu.

Change-Id: I8f431e2d261aec02581150125d11324a3ee11656