Make "Quit" menu saner

- Use 'x' for Exit shortcut
- Set Ctrl-Q as global quit key sequence

src/qt/locale/bitcoin_de.ts

@@ -351,7 +351,7 @@ Are you sure you wish to encrypt your wallet?</source>
     </message>
     <message>
         <location filename="../bitcoingui.cpp" line="200"/>
-        <source>&amp;Exit</source>
+        <source>E&amp;xit</source>
         <translation>Beenden</translation>
     </message>
     <message>

src/qt/locale/bitcoin_nl.ts

@@ -372,7 +372,7 @@ Are you sure you wish to encrypt your wallet?</source>
     </message>
     <message>
         <location filename="../bitcoingui.cpp" line="200"/>
-        <source>&amp;Exit</source>
+        <source>E&amp;xit</source>
         <translation>A&amp;fsluiten</translation>
     </message>
     <message>

src/qt/locale/bitcoin_ru.ts

@@ -343,7 +343,7 @@ Are you sure you wish to encrypt your wallet?</source>
     </message>
     <message>
         <location filename="../bitcoingui.cpp" line="200"/>
-        <source>&amp;Exit</source>
+        <source>E&amp;xit</source>
         <translation>Вы&amp;ход</translation>
     </message>
     <message>