Arch: implement new get_param functions

Additionally 2 Arch_Window bugs were fixed:
* If the W1 value was changed the box tracker was not repositioned relative to the cursor.
* The WindowColor was not applied because of a typo in the code. De current default color is quite dark BTW.

Note that all dimensional values that were not really defaults, but just the last entered values, have been removed from preferences-archdefaults.ui. As a result the layout looks a bit strange. That will be improved in a next PR.

src/Mod/Arch/ArchBuilding.py

@@ -24,6 +24,8 @@ import FreeCAD
 import ArchCommands
 import ArchFloor
 import Draft
+from draftutils import params
+
 if FreeCAD.GuiUp:
     import FreeCADGui
     from PySide import QtCore
@@ -227,8 +229,7 @@ class _CommandBuilding:
     def Activated(self):
 
         sel = FreeCADGui.Selection.getSelection()
-        p = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Arch")
-        link = p.GetBool("FreeLinking",False)
+        link = params.get_param_arch("FreeLinking")
         buildingobj = []
         warning = False
         for obj in sel :