msm7x30-common: use PRODUCT_DEFAULT_PROPERTY_OVERRIDES for default USB config

defaults.prop is now correctly updated with the property.
msm7x30-common: Enable FM audio routing
msm7x30: Enable SystemUI flags to optimize performance

We are now using fake shadows and hardware layers.
The wallpaper is now shown again, since the performance
allows it.
msm7x30-common: Remove cnd binary

Connectivity Engine Daemon is used to access mobile data & Wi-Fi simultaneously.
This feature is not needed and it causes additional dependencies.
msm7x30-common: Readd props to disable strict mode
msm7x30-common: Allow more background services

 * Some services or broadcast may get tremendous delay because
   of the limited background services. It will bring about many
   issues like alarmmanagerservice's wakelock held too long.

   (from CAF)
msm7x30-common: Set background app limit to 16

 * For low memory devices, the original limit of 24 would be
   impractical anyways since it cannot contain that many apps.

   (from CAF)