HSS 'verbs' for callback generation

[vprimachenko]

there are functions like removeFlag which are used instead of a 'code block' eg

foo {
    on.click: removeFlag(bar);
}

instead of

foo {
    on.click: ${
        this.removeFlag(bar);
    }
}

such functions need to be recognized as 'function generators' (a js equivalent would be function(a){ return function(a){ a.b() }; })

there should be functions like insertAfter etc for dom manipulation and such which will generate 'code blocks'(aka callbacks) for use as event handler
eg

@request {
    src: 'foo';
    on.complete: appendTo(@root bar);
}