docs: Mark 5.0.7 additions.

al_set_display_flag
ALLEGRO_FRAMELESS
docs: Mark 5.0.8 additions.

ALLEGRO_ALIGN_INTEGER
docs: Mark 5.0.9 additions.

al_set_display_icons
al_init_native_dialog_addon
al_shutdown_native_dialog_addon
Prepare summary of changes for 5.0.9.