Tethering: IPV6 tethering support

- Added two APIs addUpstreamV6Interface and removeUpstreamV6Interface,
  required to pass the interfaces to use to the Router Advertisement
  Proxy.
- Added a dun entry to the networkAttributes value in
  res/values/config.xml. This is to allow tethering to work with the
  dunRequired property.
- Added dun to allowable tether upstream type.
- Enabled debug flags for debug logging inside framework components.
- Regardless of MOBILE_TYPE_DUN APN being available, if dun_required
  flag is not set, fall back to HIPRI as a preferred APN for the
  embedded data call.
- Debug logging was enabled by default which was causing security
  vulnerabilities. This patch disables debug logging.
- Added a NULL check for Network info in CMD_UPSTREAM_CHANGED
- Changed the exception type thrown from IllegalStateException to
  RemoteException whenever the IPv6 tethering rules fail to apply. The
  IllegalStateException is not caught by the caller causing the JVM
  to crash. By throwing RemoteException, the caller will catch and
  print and error message instead of crashing.

Conflicts:
        services/core/java/com/android/server/NetworkManagementService.java

CRs-fixed: 665103
Change-Id: Idb0971449473554bcd749d478563db7ba351d55d
Broadcast upstream interface change event independently for IPv4 & IPv6

On change in tethering upstream interface for IPV4 or IPV6 address,
broadcast an intent with the information viz iface name, ip address
type and update type(i.e add or delete).

Change-Id: Ia80738bcf09692209674a47b6c6c1c082a201b16
CRs-Fixed: 680728
Broadcast upstream interface change event for IPV6

On change in tethering upstream interface for IPV6 address, broadcast
an intent with the information viz iface name, ip address type and
update type(i.e. add or delete). This changelist is update to
Change-Id: Ia80738bcf09692209674a47b6c6c1c082a201b16 for IPV6
tethering support.

Change-Id: I2e3da6e6b881ef1eb0f673c8d293f10c250ccd93
CRs-Fixed: 721222
SOFTAP: implement SOFTAP new requirement in framework

If framework recevied the STA (dis)connect message from netd,
it will try to read device info from dnsmasq and broadcast
an state change event via intent.
Meanwhile, framework will maintain the conneted Sta list which
can be access from upper layer.

CRs-Fixed: 685913
Change-Id: I61bfb48a9ac51371995b1992b966be6e18633828
Framework: StatusBar Ticker (1/2)

Change-Id: I6135297792c7b42172e08e14acd37b252cb00102