Create axvalue_to_pytuple to convert AXValueRef to tuples

[daveenguyen]

I was looking into issue #162 and discovered some things.

pyobjc documentation says "AXValueGetValue is not yet supported, it requires a manual wrapper."
This is a problem because AXValueGetValue was how the original c-extension of atomac was getting the value.

This PR implements a workaround by parsing the string of AXValueRef object to get the values and return a tuple like it was before.

snippet used in c-extension:

pyatom/atomac/_a11y/conversion.c

Lines 92 to 158 in 7a0e8f6

	/*
	*-----------------------------------------------------------------------------
	*
	* CGValueToPyTuple --
	*
	* Convert a CG value (CGSize, CGPoint, or CFRange) to Python tuple
	*
	* Results:
	* Returns a Python Tuple or NULL and a Python exception on
	* failure.
	*
	* Side effects:
	* Ownership of the Python Tuple object is transferred to the caller.
	*
	*-----------------------------------------------------------------------------
	*/
	PyObject *
	CGValueToPyTuple(AXValueRef value) //IN: AXValueRef to convert
	{
	PyObject *tuple = PyTuple_New(2);
	if (kAXValueCGSizeType == AXValueGetType(value)) {
	CGSize size;
	double float1 = 0.0;
	double float2 = 0.0;
	if (AXValueGetValue(value,kAXValueCGSizeType,&size) == 0){
	return NULL;
	}
	float1 = (double)size.width;
	float2 = (double)size.height;
	PyTuple_SetItem(tuple,0,Py_BuildValue("d",float1));
	PyTuple_SetItem(tuple,1,Py_BuildValue("d",float2));
	return tuple;
	}
	if (kAXValueCGPointType == AXValueGetType(value)){
	CGPoint point;
	double float1 = 0.0;
	double float2 = 0.0;
	if (AXValueGetValue(value,kAXValueCGPointType,&point) == 0){
	return NULL;
	}
	float1 = (double)point.x;
	float2 = (double)point.y;
	PyTuple_SetItem(tuple,0,Py_BuildValue("d",float1));
	PyTuple_SetItem(tuple,1,Py_BuildValue("d",float2));
	return tuple;
	}
	if (kAXValueCFRangeType == AXValueGetType(value)){
	CFRange range;
	long index1 = 0;
	long index2 = 0;
	if (AXValueGetValue(value,kAXValueCFRangeType,&range) == 0){
	return NULL;
	}
	index1 = range.location;
	index2 = range.length;
	PyTuple_SetItem(tuple,0,Py_BuildValue("l",index1));
	PyTuple_SetItem(tuple,1,Py_BuildValue("l",index2));
	return tuple;
	}
	// @@@TODO: Need to set a python exception here if not already set
	return NULL;
	}

[daveenguyen]

Using description() (objective-c's equivalance to __repr__) in conjunction with NSSizeFromString, NSPointFromString, NSRangeFromString from Foundation framework to get the value.
Then casting to tuple