reactive styles

[Alex2772]

#572

[Alex2772]

no wonder this PR has id #666

[Alex2772]

Current direction:

using Modifier like in jetpack compose. To stack modifiers, operator| is used:

Margin{} | TextColor { AColor::RED } | BackgroundSolid { AColor::BLUE }

for bindings-lua, to avoid extra object, a global Modifier object will be provided, whose implementation is close to Jetpack Compose:

Modifier = {}

-- c++ registers methods for Modifier for standard modifiers like `BackgroundSolid` and `TextColor`. This is how it would be used in lua:

Modifier:TextColor('#00f'):BackgroundSolid('#f00')

Each modifier is exposed as function and modifies Modifiers state, rather than creating lots of temporary objects.