Drop TreeBuildingView protocol

[helje5]

The TreeBuildingView should be dropped altogether.

There have still been issues with the compiler not picking the proper static HTMLTreeBuilder functions, but those are probably bugs in the signatures, or the types not being passed through properly.

The way to approach this is to completely drop the protocol. If it works, all is great :-) For buggy cases, this hits the builder function which takes View. Debug from there.