Eliminate "has no method 'forEach'" errors when the number of WebPageTest runs is 1

This should resolve Issue 532.  

I debated a bit on how to solve this issue - I could have solved it via modifying each aggregator to test whether it was an array, or I could have solved it by detecting when there is a single object being returned and wrapping it in an array.  I opted for the latter because it seems to simply the aggregator code.

I also solved two other issues:

  1. If "firstViewOnly" in wptConfig was set to true, you'd get related errors from the aggregators assuming the existence of the repeatView object.  This fix required a change in pages.js as well.
  2. Two of the aggregators for repeat view had a copy paste error and were still named "firstView".  This exposed itself during the error condition described in #1 where it named the incorrect aggregators as being in fault.  It may have corrected other issues too - I suspect that the corresponding firstView metrics were being overwritten in the summary.json file.