Merge branch 'convauto_getencoding' of https://github.com/pavel-t/wxWidgets

Add wxConvAuto::GetEncoding(), other improvements and bug fixes.

See https://github.com/wxWidgets/wxWidgets/pull/2072

interface/wx/convauto.h

@@ -146,6 +146,22 @@ public:
     */
     wxBOM GetBOM() const;
 
+    /**
+        Return the detected encoding
+
+        Returns @c wxFONTENCODING_MAX if called before the first use.
+
+        @since 3.1.5
+    */
+    wxBOM GetEncoding() const;
+
+    /**
+        Check if the fall-back encoding is used.
+
+        @since 3.1.5
+    */
+    bool IsUsingFallbackEncoding() const;
+
     /**
         Return a pointer to the characters that makes up this BOM.