Moved tests from output to outputs (close #2591)
setOutputPosition() -> parentOutputPositionChanged()

This function (on both FEProblem and Executioner) no longer sets the
output position, it just calls parentOutputPositionChanged(), so it no
longer needs to take a Point, and I'm changing the name in both
FEProblem and Executioner.

Refs #2912.
Merge pull request #2911 from aeslaughter/tests-2591

Moved tests from output to outputs
Merge pull request #2913 from jwpeterson/set_output_position

setOutputPosition() -> parentOutputPositionChanged()