Each editor tab should maintain its own edit mode selection

[x87]

After #74 each open document could have different active extensions which is difficult to implement if the edit mode configuration is shared.

• edit mode data lives in editor (syntax manager)

• closed files should restore edit mode on open

  • resolve a collision when a MRU file is opened via CLI with edit mode, CLI should control over settings.ini

• new tab inherits currently selected edit mode

  • unclear behavior on opening a compiled script (there is no editor yet) - keep existing behavior, use currently active mode

• hot reload modes.xml - update all tabs

• test $O directive - ini reload

• reload templates in all tabs when a new shared template is added

• show ERR_0001, MSG_0003 only once per session

• refresh models (IDE) when game path is updated for all tabs with the same mode (nice to have, could be a separate feature)