GitLab

The project no longer uses OrbTk.

Use reference-counted stylesheet when rendering

+ `Context` takes ownership of the theme in `Context::switch_theme()`
+ `RenderObject::render()` makes use of the reference-counted theme stored
  in the Entity Component System
+ `RenderObject::render_children()` likewise passes immutable references to
  the theme
+ Updated `showcase` example to match

Shell and ComboBox updates

* overcome lint error
Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

* remove duplicate definition assignment for
  `build_context.register_shared_property::<f32>
Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

* rearrange enum 'Key' and impl 'From<Key>' in lexical order
* add documentation for public definitions
* rearrange key_event.scancode in lexical order
* add Tabulator identifier key (K_TAB)
Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

documentation update

api: description clarification when switching entitycontext with `change_into`
widgets: typo correction in `pager`
Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

fix showcase project : Plural Planner url

Plural Planner project url is changed, 
old:   https://codeberg.org/PluralTools/Planner
new: https://codeberg.org/PluralTools/Plural

Support Alignment in theme files

Also fix some test issues

theme_fluent: MDL2-Icons v1.1.0 update

fix README.md, widgets' example has been removed on 25798a77

Fix utils build script