Implemented Bluetooth Low Energy: examples documentation

Added documentation for lowenergyscanner example together with two screenshots.

Change-Id: I3615ffee26edd5b2ce75e93adc940ba9d272f072
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Fixed couple minor things for QNX platform

Connecting error signals in QLowEnergyController, deleting pointers in descructor in QLowEnergyProcess and added loading btapi for QNX platform.

Change-Id: I8785583e38b4e9eaa7b2cf1103df4ab206392a5a
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>