added mode 'gf --run' for running silently a script ; made quizzes handle character encoding correctly ; for this end, collected coding functions in GF.Text.Coding

src/GF/Text/Coding.hs

@@ -0,0 +1,14 @@
+module GF.Text.Coding where
+
+import GF.Text.UTF8
+import GF.Text.CP1251
+
+encodeUnicode e = case e of
+  "utf8"   -> encodeUTF8
+  "cp1251" -> encodeCP1251
+  _        -> id
+
+decodeUnicode e = case e of
+  "utf8"   -> decodeUTF8
+  "cp1251" -> decodeCP1251
+  _        -> id