Use full path of executables; working directory isn't used

In this release, I resolved a bug in Appium support that rendered executables that weren't on the path unusable. Even specifying the path through the associated setting was ineffective. This was the result of a misunderstanding about how the "working directory" would be applied. This setting isn't considered when trying to resolve the absolute path of the specified executable. For executables specified solely by name, only the system path specification is used for this purpose.

I now specify the full paths of executables, and I don't bother setting the working directory.