Partial hints

needs clean up

Change-Id: I74064fc2040fc805f1d2daba43dddfa08a55e22d
Speaker icon while hovering hanzi

Change-Id: If12d980216e72cf91ec4f8569d151a667f1c27ed
Audio clip support when clicking hanzi

Needs refactoring

Change-Id: I7473e69e61e2ea3cbbb1da76d5bce9badcb42947