Use proper encoding in UnescapeString() to speed up processing

Use the proper encoding to prevent extraneous conversion encoding conversion inside UnescapeString(). This change reduces the eeschema symbol library loading time (ubuntu and windows build) from 2700ms to 1700ms.

See merge request https://gitlab.com/kicad/code/kicad/merge_requests/70

common/string.cpp

@@ -132,21 +132,21 @@ wxString UnescapeString( const wxString& aSource )
 {
     wxString converted = aSource;
 
-    converted.Replace( "{dblquote}", "\"" );
-    converted.Replace( "{quote}", "'" );
-    converted.Replace( "{lt}", "<" );
-    converted.Replace( "{gt}", ">" );
-    converted.Replace( "{backslash}", "\\" );
-    converted.Replace( "{slash}", "/" );
-    converted.Replace( "{bar}", "|" );
-    converted.Replace( "{colon}", ":" );
-    converted.Replace( "{space}", " " );
-    converted.Replace( "{dollar}", "$" );
-    converted.Replace( "{tab}", "\t" );
-    converted.Replace( "{return}", "\n" );
+    converted.Replace( wxS( "{dblquote}" ), wxS( "\"" ) );
+    converted.Replace( wxS( "{quote}" ), wxS( "'" ) );
+    converted.Replace( wxS( "{lt}" ), wxS( "<" ) );
+    converted.Replace( wxS( "{gt}" ), wxS( ">" ) );
+    converted.Replace( wxS( "{backslash}" ), wxS( "\\" ) );
+    converted.Replace( wxS( "{slash}" ), wxS( "/" ) );
+    converted.Replace( wxS( "{bar}" ), wxS( "|" ) );
+    converted.Replace( wxS( "{colon}" ), wxS( ":" ) );
+    converted.Replace( wxS( "{space}" ), wxS( " " ) );
+    converted.Replace( wxS( "{dollar}" ), wxS( "$" ) );
+    converted.Replace( wxS( "{tab}" ), wxS( "\t" ) );
+    converted.Replace( wxS( "{return}" ), wxS( "\n" ) );
 
     // must be done last
-    converted.Replace( "{brace}", "{" );
+    converted.Replace( wxS( "{brace}" ), wxS( "{" ) );
 
     return converted;
 }