Fix decoding charset parameter

To avoid a libxml bug/limitation, we were already stripping the charset
parameter, but we were not considering the single quote as valid
delimiter.

NEWS

@@ -1,4 +1,11 @@
+2.0.6 (2013-MM-DD)
+------------------
+
+Bug fixes
+ - Fixed decoding of the charset parameter when using single quotes (#2306)
+
 2.0.5a (2013-04-17)
+------------------
 
 Bug fixes
  - Fixed an issue when parsing user CN with leading or trailing spaces (#2287)

UI/MailPartViewers/UIxMailPartHTMLViewer.m

@@ -189,7 +189,7 @@ static NSData* _sanitizeContent(NSData *theData)
 	      j = 8;
               found_delimiter = YES;
 
-	      while (*(bytes+j) != ' ' && *(bytes+j) != '"')
+	      while (*(bytes+j) != ' ' && *(bytes+j) != '"' && *(bytes+j) != '\'')
 		{
 		  j++;