Improvements for BOA

- Allowed write buffers to become very large in asynnet. Thus in order to allow for the transfer
  of large images. tested ub to 2kx2k, 16MB
- Handle lack of space in the write buffer more gracefully: just skip the image

asynnet.h

@@ -145,6 +145,14 @@ int ANETinfo(int handle, char *hostname, int hostNameLen);
  * \return 1 on success, 0 on failure
  */
 int ANETwrite(int handle, void *buffer, int count);
+/**
+ * \brief Test if the buffer can be written to the network
+ * \param handle The handle for the connection
+ * \param buffer A pointer to the data to write
+ * \param count The number of bytes to write.
+ * \return 1 when possible, 0 when buffer overrun
+ */
+int ANETcanWrite(int handle, void *buffer, int count);
 /**
  * \brief copy at max bufferLength bytes into buffer. The data is not deleted from 
  *  the read buffer yet.