minor changes in Mapsui.Renderin.OpenTK
just Formatting of FpsCounter.cs
Mapsui.Rendering.OpenTK.Tests show FPS without cap at 60.
adding BitmapRegistry.cs
using BitmapRegistry in opentk point symbol
adapting for int ResourceId
deleting SharpMap tests that have been replaced with Mapsui tests.
adding test image tilelayer.png
adding test image points_with_symbolstyle.png
updating test images.
rendering xaml tests: writing output png's to separate file.
replacing SymbolStyle.Bitmap with SymbolStyle.ResourceId
gdi rendering: updating for change in bitmap symbols
xaml rendering: updating for change in bitmap symbols
xaml mapcontrol: just layout
minor changes to rendering tests.
renaming ResourceId to BitmapId
adding InitialzedViewport event to ios MapControl.
using render resolution in retrieving viewportchanged
adding ViewportInitialized event.