Rework how progress dialog is used

gui/utils/progressHelper.py

@@ -0,0 +1,19 @@
+class ProgressHelper:
+
+    def __init__(self, message, maximum=None, callback=None):
+        self.message = message
+        self.current = 0
+        self.maximum = maximum
+        self.workerWorking = True
+        self.dlgWorking = True
+        self.error = None
+        self.callback = callback
+        self.cbArgs = []
+
+    @property
+    def working(self):
+        return self.workerWorking and self.dlgWorking and not self.error
+
+    @property
+    def userCancelled(self):
+        return not self.dlgWorking