implemented image#mapcolorlevel()
added test case for image#mapcolorlevel()
MemoryDC is owned by gura's object
implementing wx.Region
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot
implementing gurashot