lot of changes
- dialog.previous & dialog.box are deprecated ... will be removed soon
- dialog.page( obj=None ) permits to display or hide a full page
- dialog.alert can now override the width size only, with size:float parameter
- and lot of little fixes in the 4ui
**Full Changelog**: https://github.com/manatlan/htagui/compare/v0.4.2...v0.5.0