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/TLSOutStream.h

@@ -36,20 +36,20 @@ namespace rdr {
     virtual ~TLSOutStream();
 
     void flush();
-    int length();
+    size_t length();
 
   protected:
-    int overrun(int itemSize, int nItems);
+    size_t overrun(size_t itemSize, size_t nItems);
 
   private:
-    int writeTLS(const U8* data, int length);
+    size_t writeTLS(const U8* data, size_t length);
     static ssize_t push(gnutls_transport_ptr_t str, const void* data, size_t size);
 
     gnutls_session_t session;
     OutStream* out;
-    int bufSize;
+    size_t bufSize;
     U8* start;
-    int offset;
+    size_t offset;
   };
 };