osk fix for single quote and backtick

Change the behavior of the onscreen keyboard's quote and backtick such
that clicking them once displays the clicked key.

Previously they defaulted to composing an accented character, as
discussed here:

  https://sourceforge.net/p/tuxpaint/mailman/message/37656169/

osk/abc.h_layout

@@ -85,7 +85,7 @@ KEY 24 1.0 q Q ä Ä 1
 KEY 27 1.0 r R ® ® 1
 KEY 39 1.0 s S ß § 1
 KEY 47 1.0 ; : ¶ ° 0
-KEY 48 1.0 ´ ¨ ' " 0
+KEY 48 1.0 ' " ´ ¨ 0
 
 # Return
 KEY 36 2.0 ENTER ENTER ENTER ENTER 0