Wishlist: Ideal UI library for Nim

[alexeypetrushin]

Markup should be avoided. With non-nim markup, you won't get type safe event 
handlers, or a safe way to pass data, inputs, events, bindings, up/down 
component hierarchy. A problem on that way is a refusal of Nim to improve Nim 
DSL capabilities. Need to specify things like `auto`, bloated `do` block 
syntax, inability of () => macro for multiline, etc.