Fix the language picker and tidy the graphics tab

Both language combos decided a change was the user's by checking
IsKeyboardFocusWithin on the picked item. Selecting with the mouse leaves the
focus on the combo, not on the item, so on Windows the check failed and the
language never changed. The handlers now compare the picked code with the one
already loaded instead of guessing who caused the event: filling the combo in
selects what is loaded and stops there, a real pick differs and applies.

The settings tab listed a hard-coded Polski / English pair and wrote the
language back as "Polski" or "English", so picking Czech, Hungarian or
Russian in the top bar was overwritten on save. It is filled from lang/ now,
and writes back the selected entry.

LocalizationService gains a LanguageChanged event: the main window rebuilds
the captions that code builds once (train stats, panel headers, combo items)
from there, so a pick in either place refreshes them. Its PropertyChanged
also names the indexer "Item[]", which is what bindings listen for.

Graphics tab: the track-curve quality slider moves over from Physics, the
view angle shows a degree sign instead of the Polish "stopni", and the HDR
tone-mapping picker is gone - only Reinhard.glsl ever shipped, so
ApplyHdrShader copies that one and the starter.hdr setting is dropped.

StarterNG/startercfg/lang/cz.xml

@@ -223,7 +223,6 @@
     <String key="Yes">Ano</String>
     <String key="No">Ne</String>
     <String key="TabInfo">Informace</String>
-    <String key="HdrToneMap">Mapování tónů HDR</String>
     <String key="SettingsFileChangedTitle">Nastavení</String>
     <String key="SettingsFileChanged">Soubor eu07.ini byl změněn mimo starter. Načíst jej znovu?</String>
     <String key="AddAllCategory">Přidat celou kategorii</String>

StarterNG/startercfg/lang/en.xml

@@ -223,7 +223,6 @@
     <String key="Yes">Yes</String>
     <String key="No">No</String>
     <String key="TabInfo">Info</String>
-    <String key="HdrToneMap">HDR tone mapping</String>
     <String key="SettingsFileChangedTitle">Settings</String>
     <String key="SettingsFileChanged">eu07.ini was changed outside the starter. Reload it?</String>
     <String key="AddAllCategory">Add whole category</String>

StarterNG/startercfg/lang/hu.xml

@@ -223,7 +223,6 @@
     <String key="Yes">Igen</String>
     <String key="No">Nem</String>
     <String key="TabInfo">Információ</String>
-    <String key="HdrToneMap">HDR tónusleképezés</String>
     <String key="SettingsFileChangedTitle">Beállítások</String>
     <String key="SettingsFileChanged">Az eu07.ini fájl a starteren kívül módosult. Újratölti?</String>
     <String key="AddAllCategory">Teljes kategória hozzáadása</String>

StarterNG/startercfg/lang/pl.xml

@@ -223,7 +223,6 @@
     <String key="Yes">Tak</String>
     <String key="No">Nie</String>
     <String key="TabInfo">Informacje</String>
-    <String key="HdrToneMap">Tone mapping HDR</String>
     <String key="SettingsFileChangedTitle">Ustawienia</String>
     <String key="SettingsFileChanged">Plik eu07.ini został zmieniony poza starterem. Wczytać ponownie?</String>
     <String key="AddAllCategory">Dodaj całą kategorię</String>

StarterNG/startercfg/lang/ru.xml

@@ -223,7 +223,6 @@
     <String key="Yes">Да</String>
     <String key="No">Нет</String>
     <String key="TabInfo">Информация</String>
-    <String key="HdrToneMap">Тональная компрессия HDR</String>
     <String key="SettingsFileChangedTitle">Настройки</String>
     <String key="SettingsFileChanged">Файл eu07.ini изменён вне стартера. Загрузить заново?</String>
     <String key="AddAllCategory">Добавить всю категорию</String>