Fix memory leak issue in application settings

If opening Main menu->Settings->Apps, and rotating the phone
about 50 times, Settings force closes and out of memory occur.
This is because after ManageApplications onDestroy, references
of ApplicationsState have not been release. So, they will not
be garbage collected. It leads to OOM and force close. To
avoid this we need to release the references of
ApplicationsState when ManageApplications onDestroy.

Also, when exiting ManageApplications or InstalledApps in
Settings there is a memory leak due to not releasing some
objects. This fix releases the Session objects to avoid
memory leak.

Change-Id: Icca7100bded0653a4ec7f2b4bd48a29262432a3b
Update AP signal strength on signal level changed

Patch related to bug GMIN-1381 "The AP signal strength is display
different in notification bar and WIFI settings"

On behalf of Ernest P Chen:
Update all access points when reacting to a broadcast that the signal
level changed.

Change-Id: If690212b9d4640d236747eacef9a4ac8c4c98cd9
Signed-off-by: Frederic Danis <frederic.danis@intel.com>
Signed-off-by: Yong Yao <yong.yao@intel.com>
Match signal level between Settings and NetworkController

Patch related to bug GMIN-1381 "The AP signal strength is display
different in notification bar and WIFI settings"

On behalf of Ernest P Chen:
match up signal level better by deriving WifiSettings level based on 5
levels similar to NetworkController.

Change-Id: I7da239a6d83b52a9563298f333e9b692084fbd20
Signed-off-by: Frederic Danis <frederic.danis@intel.com>
Signed-off-by: Yong Yao <yong.yao@intel.com>