Added wxD2DPenData declaration and skeleton implementation
Added missing implementation comment
Added conversion function from wxPenCap to D2D1_CAP_STYLE
Added conversion function from wxPenJoin to D2D1_LINE_JOIN
Added conversion function from wxPenStyle to D2D1_DASH_STYLE
Renamed pen conversion methods
Added width data member to wxD2DPenData and updated constructor
Partially implemented wxD2DPenData::CreateStrokeStyle()
Added const qualifiers to non-modifiable wxD2DPenData data members
Added conversion method from wxColour to D2D1_COLOR_F
Changed wxD2DPenData to hold a pointer to a ID2D1RenderTarget instead of ID2D1Factory, since device-dependent resources are created via render targets
Added partial implementation for wxD2DPenData::EnsureInitialized() which ensures pens with solid colour are properly initialized
Added wxD2DContext::CreatePen(const wxPen&) for creating graphics wxGraphicsPen objects. These objects cannot be constructed via the wxD2DRenderer, because they are device-dependent resources and need a render target to construct them.