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/FdOutStream.h

@@ -34,7 +34,7 @@ namespace rdr {
 
   public:
 
-    FdOutStream(int fd, bool blocking=true, int timeoutms=-1, int bufSize=0);
+    FdOutStream(int fd, bool blocking=true, int timeoutms=-1, size_t bufSize=0);
     virtual ~FdOutStream();
 
     void setTimeout(int timeoutms);
@@ -42,20 +42,20 @@ namespace rdr {
     int getFd() { return fd; }
 
     void flush();
-    int length();
+    size_t length();
 
     int bufferUsage();
 
     unsigned getIdleTime();
 
   private:
-    int overrun(int itemSize, int nItems);
-    int writeWithTimeout(const void* data, int length, int timeoutms);
+    size_t overrun(size_t itemSize, size_t nItems);
+    size_t writeWithTimeout(const void* data, size_t length, int timeoutms);
     int fd;
     bool blocking;
     int timeoutms;
-    int bufSize;
-    int offset;
+    size_t bufSize;
+    size_t offset;
     U8* start;
     U8* sentUpTo;
     struct timeval lastWrite;