QtIFW

add executableExtension to default templateBinary on windows

 - and use a better name for binaryEnding -> executableExtension

Change-Id: Ie0ab28152f6a9f1c8e93b0fcd2cf3eb2a976122a
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>
Reviewed-by: Niels Weber <niels.weber@digia.com>