Integrate Werners & Jans double branch

Move from float to double
Further suggestions for float -> double move
Moved Tools2D from float to double
More suggestions for float->double move from Gui subdirectory
Changes to FEM constraint visuals for float->double move
Suggested changes for float -> double move
Suggestions for Part module moving float -> double

src/App/PropertyUnits.cpp

@@ -116,12 +116,12 @@ void PropertyLength::setPyObject(PyObject *value)
     setValue(UnitsApi::toDblWithUserPrefs(Length,value));
  
 #else   
-   float val=0.0f;
+   double val=0.0f;
     if (PyFloat_Check(value)) {
-        val = (float) PyFloat_AsDouble(value);
+        val = PyFloat_AsDouble(value);
     }
     else if(PyInt_Check(value)) {
-        val = (float) PyInt_AsLong(value);
+        val = (double) PyInt_AsLong(value);
     }
     else {
         std::string error = std::string("type must be float or int, not ");