AudioService: Reduce volume to safe level when headset is connected (2/2)

This is a safety feature for users who opt to raise volume above the designated
safe level while using a headset.

Currently when a user does this they are provided with no protection against
dangerously high volume levels until the next time the headset volume warning
is displayed.

This patch adds an optional feature to ensure volume is no higher than the safe
level every time a headset is connected.

Change-Id: Idaa9cc9549bc3c6278e1e44490433c5366c29c16
NetworkController: Extra WIMAX icon handling

- Fixes the dependency on 3g (or other mobile data)
  being connected for the wimax (4G) icon to show.
- Prevents the lack of mobile data (3g, 1x, etc) from
  removing the wimax icon if wimax is connected.
- Continue to show the network carrier type if
  phone is out of service but wimax is still connected.

Authored by: Matt Merhar

Change-Id: Ib1cf411cf4e7248248e093b6a7317fbe5d80f704