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/Tools2D.cpp

@@ -431,6 +431,37 @@ void Polygon2d::Intersect (const Polygon2d &rclPolygon, std::list<Polygon2d> &rc
     rclResultPolygonList.push_back(clResultPolygon);
 }
 
+bool Polygon2d::Intersect (const Polygon2d &other) const {
+    if(other.GetCtVectors()<2 || GetCtVectors() < 2)
+        return false;
+
+    for(auto &v : _aclVct) {
+        if(other.Contains(v))
+            return true;
+    }
+
+    if(Contains(other[0]))
+        return true;
+
+    for(size_t j=1; j<other.GetCtVectors(); ++j) {
+        auto &v0 = other[j-1];
+        auto &v1 = other[j];
+
+        if(Contains(v1))
+            return true;
+
+        Line2d line(v0, v1);
+        for(size_t i=0; i<GetCtVectors(); ++i) {
+            Line2d line2(At(i), At((i+1)%GetCtVectors()));
+            Vector2d v;
+            if(line.IntersectAndContain(line2, v))
+                return true;
+        }
+    }  
+    return false;
+}
+
+
 bool Polygon2d::Intersect (const Vector2d &rclV, double eps) const
 {
     if (_aclVct.size() < 2)