API breaks during Tepl 6: libgedit-tepl 6 Reference Manual

## API breaks during Tepl 6

There are also ABI breaks not affecting the API, so just re-compiling the program is sufficient in that case.

Tepl 6.0 to Tepl 6.2:

- The `tepl_utils_override_font()` function has been renamed to tepl_utils_override_font_string().

Tepl 6.2 to Tepl 6.4:

- The `tepl_statusbar_*()` functions have been removed, you can use TeplLineColumnIndicator instead.

Tepl 6.4 to Tepl 6.6:

- Tepl now depends on libgedit-gtksourceview instead of GtkSourceView.

- The `TeplWidgetListItem` and `TeplWidgetListCategory` classes have been removed.

Tepl 6.6 to Tepl 6.8:

- The `TeplPanel` class has been renamed to TeplPanel1.

- The `TeplStack`, `TeplStackItem` and `TeplStackSwitcherMenu` classes have been removed. They are superseded by TeplPanel (and related classes and interfaces).

- The `TeplStatusbar` class has been removed, and is replaced by tepl_utils_setup_statusbar().

Tepl 6.8 to libgedit-tepl 6.10:

- Tepl has been renamed to libgedit-tepl. The new pkg-config name is: `libgedit-tepl-6`

- TeplFile now uses GflsUnsavedDocumentTitles. This affects the TeplFile:short-name property. Also, `tepl_file_set_untitled_file_callback()` and `TeplUntitledFileCallback` have been removed.

libgedit-tepl 6.10 to 6.11:

- The `TeplSettingsSimpleThemeVariant` enum, `tepl_settings_handle_simple_theme_variant()` and `tepl_prefs_create_simple_theme_variant_combo_box()` have been removed. You can use instead the more complete TeplSettingsThemeVariant enum and the functions that use it.

- `tepl_buffer_provide_style_scheme_id_gsetting()` has been removed. Use TeplSettings instead to provide two GSettings keys instead of one.

  The `TeplBuffer:tepl-style-scheme-id` property, `tepl_buffer_get_style_scheme_id()` and `tepl_buffer_set_style_scheme_id()` have been removed. You can use tepl_buffer_connect_style_scheme_settings() instead.

- `tepl_prefs_create_color_scheme_component()` and the `TeplStyleSchemeChooserWidget` class have been removed. They are replaced by TeplStyleSchemeChooserSimple and TeplStyleSchemeChooserFull.

- TeplTabLabel now inherits from `GtkBox` instead of `GtkGrid`.

- TeplPanelItem is now a GObject class instead of an interface.

- The API of tepl_panel_add() and its vfunc have changed.

- The API of TeplPanelSwitcherMenu has changed.

- The `TeplPanelSwitcherNotebook` class has been removed, you can use TeplPanelNotebook instead.

- The `TeplPanelContainer` class has been removed, you can use TeplPanelSimple instead.

libgedit-tepl 6.11 to 6.12:

- The `tepl_prefs_create_display_grid_checkbutton()` function has been removed.

libgedit-tepl 6.12 to 6.13:

- The `tepl_abstract_factory_fill_prefs_dialog()` function and its vfunc have been replaced by tepl_abstract_factory_create_prefs_dialog().

- The `TeplEncoding` interface and the `TeplEncodingIconv` class have been removed.