Data traffic details: use proper string for System UID

Android System ≠ Android OS (second is a "kernel" process).
Mind the numbers:
http://goo.gl/YnFvHa (actual "system" process)
http://goo.gl/XwoISO ("system" process displayed as "kernel")
http://goo.gl/sJ9yMi ("kernel" process with different traffic data)

Depends on http://review.cyanogenmod.org/63190

Change-Id: I6f6662b7adaee069ec5f29c6926b8fbce796917d
Display BTH connected status correctly

This patch removes incorrect condition.
(to not use LocalBluetoothProfile#isPreferred())
This condition uses the priority that already disconnected profile,
so this codition always returns false.

To verify this issue:
1. Turn on Bluetooth.
2. Pair and connect to BTH(A2DP/HFP)
3. The display now says "Connected"
3. Disconnect HFP profile
4. The display still says "Connected" but it should say "Connected (no phone)"

Change-Id: I9e2bfa6d23bf1be7587c9556b4b05459d02c4817
Settings: check if NfcAdapter is null

according to the javadoc, getDefaultAdapter(Context) can return null, if
no NFC adapter exists.

check if adapter is null before trying to call isEnabled

Change-Id: I7ff5488cc3b53ce9785c3e46effcf29dc31fe0ef
Settings: Add default value for display color control (2/2)

Change-Id: I50b684abe504c21ef49492f99b18873d75509697