Use subsets and or types where appropriate

[jonathanstowe]

There are a number of places where parameters to methods have a where constraint that is repeated several times, such as line and rectangle which have:

List :$location (Int $x1 where { $x1 >= 0 }, Int $y1 where { $y1 >= 0 })

This could be a reusable subset, also in these cases there could be an actual Point type with appropriate multis and coercions.