Implement CmCard equals to use Card ID.

Change-Id: Ifb2bffce1b4cac7e5ff73f6993880eaa9f5a0b58
Do not set Card category if it is empty.

The default value for category of an ApiCard is NO_CATEGORY (set in the
superclass, CmCard). If the underlying CardData has no Category, do not
overwrite the existing value.

Change-Id: If232c6f24c2dff823c276fc2280f31a9794ca45c
Fix bug that onRefreshRequested was not called.

The CmHomeCardChangeReceiver did not call onRefreshRequested when the
Broadcast was received, as it should have. Differentiate between
onCardDeleted and onRefreshRequested.

Change-Id: I721ce99b1a94ccdea434fcebd09799c95642e903