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/Tools.h

@@ -187,6 +187,33 @@ private:
 
 // ----------------------------------------------------------------------------
 
+template<typename Flag=bool>
+struct FlagToggler {
+
+    Flag &flag;
+    bool toggled;
+
+    FlagToggler(Flag &_flag)
+        :flag(_flag),toggled(true)
+    {
+        flag = !flag;
+    }
+
+    FlagToggler(Flag &_flag, Flag check)
+        :flag(_flag),toggled(check==_flag)
+    {
+        if(toggled)
+            flag = !flag;
+    }
+
+    ~FlagToggler() {
+        if(toggled)
+            flag = !flag;
+    }
+};
+
+// ----------------------------------------------------------------------------
+
 template<typename Status, class Object>
 class ObjectStatusLocker
 {
@@ -217,6 +244,23 @@ private:
 
 // ----------------------------------------------------------------------------
 
+template<typename T>
+class BitsetLocker
+{
+public:
+    BitsetLocker(T& flags, std::size_t flag, bool value = true) 
+        : flags(flags), flag(flag)
+    { oldValue = flags.test(flag); flags.set(flag,value); }
+    ~BitsetLocker()
+    { flags.set(flag,oldValue); }
+private:
+    T &flags;
+    std::size_t flag;
+    bool oldValue;
+};
+
+// ----------------------------------------------------------------------------
+
 class ConnectionBlocker {
     typedef boost::signals2::connection Connection;
     typedef boost::signals2::shared_connection_block ConnectionBlock;