[patch] support Khmer language

[Uwe Stöhr]

polyglossia supports the Khmer (Cambodian) language. LyX can therefore 
support this language too easily.

OK to go on?
regards Uwe
diff --git 
"a/C:\\Users\\Usti\\AppData\\Local\\Temp\\TortoiseGit\\lanB3F1.tmp\\languages-27ce44d-left"
 "b/D:\\LyXGit\\Master\\lib\\languages"
index 2a5d6fe..84475db 100644
--- 
"a/C:\\Users\\Usti\\AppData\\Local\\Temp\\TortoiseGit\\lanB3F1.tmp\\languages-27ce44d-left"
+++ "b/D:\\LyXGit\\Master\\lib\\languages"
@@ -687,6 +687,14 @@ Language kazakh
        EndPostBabelPreamble
 End
 
+# not supported by babel
+Language khmer
+       GuiName          "Khmer"
+       PolyglossiaName  khmer
+       Encoding         utf8
+       LangCode         km_KH
+End
+
 Language korean
        GuiName         "Korean"
        Encoding        euc-kr
@@ -919,7 +927,7 @@ Language serbian-latin
        GuiName          "Serbian (Latin)"
        BabelName        serbian
        PolyglossiaName  serbian
-       PolyglossiaOpts  "script=latin"
+       PolyglossiaOpts  "script=Latin"
        QuoteStyle       german
        Encoding         iso8859-2
        LangCode         sr_RS-Latin