function to check if user and printer is operational

clean up the jinja a bit too

octoprint_estop/static/js/estop.js

@@ -7,10 +7,16 @@ $(function() {
         var self = this;
 		//see if we're logged in and the printer is operational (for en/disable of button)
         self.loginState = parameters[0];
-        self.terminal = parameters[1];
-        
+        self.printerState = parameters[1];
+ 		
+		self.enableEstop = ko.pureComputed(function() {
+            return self.printerState.isOperational() && self.loginState.isUser();
+        });
+		
 		self.sendEstopCommand = function () {
-            OctoPrint.control.sendGcode("M112"); //should this ever be a variable? M112 universal?
+			if (self.enableEstop()) {
+				OctoPrint.control.sendGcode("M112"); 
+			};
         };
     }
 
@@ -18,7 +24,7 @@ $(function() {
         construct: EstopViewModel,
         dependencies: [
 			"loginStateViewModel", 
-			"terminalViewModel",
+			"printerStateViewModel",
 			],
         elements: ["#sidebar_plugin_estop"]
     });