Base: misc patches

Convenience macros/function (in Interpreter.h)

* FC_PY_GetObject/Callable(), look for callables in a python object,
  which will be used in future patch to improve performance in various
  python observer/features.

* pyCall(WithKeywords)(), helper function to invoke the callable

Matrix4D:

* hasScale(), check if there is any scale in the transformation. If so,
  further check if the scale is uniform or not. This will be used in
  future patch for Part::TopoShape to decide which type of transform to
  apply.

Placement:

* translate/rotate(), new convenience API

Rotation:

* isSame/multiVec(), new convenience API

Polygon2d:

* Intersect(), GetCenter(), new convenience API.

FlagToggler:

* New class for exception safe flag toggling, similar to StateLocker
  but with template (actually, FlagToggler is added earlier by me).

BitsetLocker:

* New class for exception manipulation of a std::bitset variable.

src/Base/Matrix.h

@@ -136,6 +136,8 @@ public:
   /// scale for the x,y,z value
   void scale        (const Vector3f& rclVct);
   void scale        (const Vector3d& rclVct);
+  /// Check for scaling factor, 0: not scale, 1: uniform scale, or else -1
+  int hasScale(double tol=0.0) const;
   /// Rotate around the X axis (in transformed space) for the given value in radians
   void rotX         (double fAngle);
   /// Rotate around the Y axis (in transformed space) for the given value in radians