Use size_t for lengths in stream objects

Provides safety against them accidentally becoming negative because
of bugs in the calculations.

Also does the same to CharArray and friends as they were strongly
connection to the stream objects.

common/rdr/HexInStream.h

@@ -26,21 +26,21 @@ namespace rdr {
   class HexInStream : public InStream {
   public:
 
-    HexInStream(InStream& is, int bufSize=0);
+    HexInStream(InStream& is, size_t bufSize=0);
     virtual ~HexInStream();
 
-    int pos();
+    size_t pos();
 
     static bool readHexAndShift(char c, int* v);
-    static bool hexStrToBin(const char* s, char** data, int* length);
+    static bool hexStrToBin(const char* s, char** data, size_t* length);
 
   protected:
-    int overrun(int itemSize, int nItems, bool wait);
+    size_t overrun(size_t itemSize, size_t nItems, bool wait);
 
   private:
-    int bufSize;
+    size_t bufSize;
     U8* start;
-    int offset;
+    size_t offset;
 
     InStream& in_stream;
   };