New Features

GdiImageLayerProxy class
AsyncLayerProxyLayer class
MiniMapControl (thanks @becio)
Allow use of SharpSbn spatial index
Add IMapTool interface to write custom tools for SharpMap.UI
Add WPF Control wrapping MapBox (thanks @petlof)
Allow setting zoom by scale (thanks @petlof)
GeoPackage provider
SharpDX layer
Added ISession interface to configure GeometryFactory and Reprojection facilities.
Graticule map decoration (thanks @terribletim)
Add LayerListImageGenerator (thanks for fine-tuning @terribletim)

Improvements

Update of GeoAPI to v1.7.5 and NetTopologySuite to v 1.15.x
OracleSpatialProvider (thanks @petlof)
WmsLayer (thanks @becio)
Handling of FeatureTable, FeatureTableCollection, FeatureDataSet
Updated GDAL/OGR to v2.4.2
Moved BruTileLayer to seperate project, updated BruTile to v2.x
KmlProvider (thanks @becio, @terribletim)
Quick accurate label collision detection
Make IProvider interface generic
Added ToSource and ToTarget reprojection methods to Layer class
Add LayerTitle property to ILayer interface
Various improvements for SqlServer2008 and SqlServerSpatialObjects provider
(thanks @joriswit, @petlof, @terribletim)
ScaleBar adjustments for WebMercator (thanks @terribletim)
MapTransform (thanks @terribletim)
Refactor OleDb__Provider to Db__Provider (thanks @joriswit)
Move map image generation for MapBox to LegacyMapImageGenerator,
wrap functionality in IMapImageGenerator interface
Handle sub-datasets in GdalRasterLayer

Thanks to all who have helped to make this possible, especially (in no specific order) @becio, @petlof, @joriswit, @terribletim