Upgrade PowerArgs to 2.0
Handle missing ArgShortcut attribute
Repl should not be true

in ShouldHandleScriptNameStartingWithRepl
Revert previous commit
Merge pull request #658 from vgrigoriu/dev

Update PowerArgs to 2.0
adds a -logfile switch for mirroring all console messages to a file
#656 changed from -logfile to -output
#656 removed duplicate arg shortcut to please PowerArgs 2.x