ensure the same working dir for all MSVC compiler calls

Per product, the working dir for MSVC compiler calls must remain the
same, because the calls share the file vc110.pdb (the exact file
name depends on the VS version).

Task-number: QBS-398
Change-Id: Idb865eb11f648e8103d91ae8a9fd43ecb9dc8a46
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
fix Windows SDK lookup for x86_64 build

64 bit builds of qbs must look in the Wow3264 registry tree.
We already did that for VS but not for the SDKs.

Change-Id: If96b7d184816c20b7075c5392bc1fdbb45d6f01d
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
use the Windows SDK version, not the ProductVersion

The "ProductVersion" of the Windows SDK is mostly useless for the
user. Also, it can contain strange values like "6.2..9200",
so better don't use it.

Change-Id: I8c56979e4c020215558e328e0d936a8e0765554b
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
simplify output of detect-toolchains

Don't display the Windows SDK version on a separate line.

Change-Id: I48d4127c32145e4bde0138f2cfb960378a56c4f4
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>