Changing BuildConfiguration(.xml) in 4.16

[jimsnomis]

On 4.27 at least, the xml is now:

<?xml version="1.0" encoding="utf-8" ?>
<Configuration xmlns="https://www.unrealengine.com/BuildConfiguration">
		<ParallelExecutor>
			<ProcessorCountMultiplier> 0.7 </ProcessorCountMultiplier>
			<bStopCompilationAfterErrors> true </bStopCompilationAfterErrors>
		</ParallelExecutor>
</Configuration>