BuildExecutePipeline: Make out-default optional
BuildExecutePipeline: Make out-default optional

Out-Default is appropriate when the results of a pipeline are not
assigned to a variable.

Also, don't set MergeMyResults. Maybe this is important, but I don't
understand it yet. Later.

mrward/Pash,sillvan/Pash,ForNeVeR/Pash,mrward/Pash,mrward/Pash,WimObiwan/Pash,sillvan/Pash,Jaykul/Pash,JayBazuzi/Pash,sburnicki/Pash,sillvan/Pash,sburnicki/Pash,mrward/Pash,WimObiwan/Pash,sillvan/Pash,Jaykul/Pash,ForNeVeR/Pash,Jaykul/Pash,JayBazuzi/Pash,ForNeVeR/Pash,JayBazuzi/Pash,WimObiwan/Pash,ForNeVeR/Pash,WimObiwan/Pash,Jaykul/Pash,JayBazuzi/Pash,sburnicki/Pash,sburnicki/Pash