PartDesign: move common code for TaskDlg{SketcherBased,DressUp}Parameters into new base class

Added a new class: TaskDlgFeatureBased which currently contains common
code for TaskDlgSketcherBasedParameters::reject() as well as the same
methode for TaskDlgDressUpParameters.
It's likely that other Feature task dialogs will inherit this class too.

src/Mod/PartDesign/Gui/TaskPadParameters.cpp

@@ -484,7 +484,7 @@ TaskDlgPadParameters::~TaskDlgPadParameters()
 bool TaskDlgPadParameters::accept()
 {
 
-    // save the history 
+    // save the history
     parameter->saveHistory();
 
     try {