support for permalink and external url

Consolidate GetURL AppleEvent handling into AppDelegate+Scriptability
file
Add scripting access groups to sdef
Add exists command
Add ‘permalink’ and ‘external url’ properties to the article scripting
object
Add a unit test to verify the behavior of ‘current article’

EvergreenTests/ScriptingTests/scripts/uiScriptingTestSetup.applescript

@@ -0,0 +1,18 @@
+-- this script sets up Evergreen so it is ready to be tested
+-- to get a current article
+
+to activateEvergreen()
+	tell application "Evergreen"
+		activate
+	end tell
+end activateEvergreen
+
+tell application "System Events"
+	set isFrontmost to frontmost of process "Evergreen"
+	repeat while isFrontmost is false
+		my activateEvergreen()
+		set isFrontmost to frontmost of process "Evergreen"
+	end repeat
+end tell
+
+return {test_result:true, script_result:"finished"}