New Features

Implemented directional FOV for FOV class (sort of)
- Technically, this was already partially in thanks to a version control mistake, however the implementation was not complete previously
- FOV can take an angle and a span, and calculate FOV as a cone meeting the specified parameters.
Added an additional parameter to FOV to take its MapView as IMapView<bool>, to simplify the 90% of cases where the map is created with each cell either blocking FOV or not
- Added BooleanFOV property to FOV to expose the result similarly as booleans (either visible or not)
Added RandomItem extension methods to IMapView that return the item at a random position
Added RandomPosition overload specialized for HashSet, and an overload that takes arguments as params

Tweaks

Modified ISettableTranslationMap<T1, T2>.ApplyOverlay function to make it simply an ISettableMapView<T> extension.
- Since the signature is the same, this should not cause backwards compatibility issues, however IF you are using ApplyOverlay currently in a .cs file that does not have using GoRogue.MapViews (which is extremely unlikely given that any map views are also defined in that namespace), you will have to add that using statement to the file.
Modified radius parameter given to SenseSource instances and FOV.Calculate to be a double rather than an int,to properly support all Euclidean distances