Allow sdktool to run in an elevated context

This fixes an issue with installation on Mac: We run sdktool with
'elevated' rights if we e.g. install in a global directory, forcing
the effective user id to be 0. However, since Qt 5.3.0 QCoreApplication
aborts if geteuid() != getuid().

Change-Id: I678f405fc0cb31dbf9c0487f674bb8dbe5e2e95e
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Update qbs submodule.

To the head of the 1.2 branch.

Change-Id: I2bd0460553afa6a8fba0bf01cfa2addc06a043b5
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
Doc: checking include paths in C++ Code Model Inspectors

Change-Id: Ia9c65df9c2e542b135f3eccb3dfdc137c03f732a
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Merge remote-tracking branch 'origin/3.1'

Conflicts:
	src/shared/qbs

Change-Id: I9567aa9331c3674cdce50b940c3ec2b5def7bd3f