v0.13.0

Breaking changes

• Update enum-map fron 0.5 to 0.6

API updates

• Add Effect::Strikethrough (not supported on ncurses)
• Add ListView::remove_child
• Replace xursive::CbFunc with Box<FnOnce>
• Add ScrollView::{inner_size, is_as_{bottom, top, left, right} }
• Add getters for current value in SliderView
• More fields made public in cursive::logger
• Add a "puppet" backend for testing and instrumentation

Improvements

• Performance improvements for the crossterm backend

Bugfixes

• Fix a possible panic when a TextView is updated asynchronously while it's being layed out.
• Fixed weird behaviour of SizeConstraint::Full with ScrollView.