Pushing onto the navstack will close the top item

##Navstack

Closeable

To bring symmetry to the navstack when an item is pushed on to the stack the (current) top item on the stack will be closed if it implements the Closable interface. This is just like popping the stack.

It is assumed that any resources you need to "Start" are setup in the bubble teaInitfunc which is always invoked before turning over control of the to the new model at the top of the stack.

Ordering

When pushing or popping models from/to the stack. The model's Init func is now always called before the model.Update with the WindowSizeMsg (used to force a size update). The resulting commands will be invoked sequentially. This maybe overkill as there should not be coupling between model setup and window sizing.

Menu Bug Fix

Menu help was not disappearing when a second press of the help key happens.

Styling changes

Mostly changes to styling and adding usage of emoji in the examples.

Menu:

• Add SetShowTitle(bool) to control if the menu title is displayed.

BreadCrumbs:

• Styling is now exposed for customization.

Default Styles:

• Little less bland.

Improve menu and navstack bugfixes

This release is mostly bugfixes and build automation changes

Documentation Improvements

There was severe lack of doc comments which has been corrected.

Initial Preview Release

This is an initial release targeting our minimum functionality for components which support navigation, menus, and breadcrumbs in a bubble tea TUI application.