Synopsis:	edit-batch-line line_number edited_line

Description:	replaces existing command line from the currently active batch
				with the specified line number with the new one.

Arguments:

	line_number		- the line number of the existing command line in the batch.
					Line numbers start with 1. So, the value of the argument must be
					in the range from 1 to the number of the last command in the batch.
					
	edited_line		- the new value for the command line which will replace the current one.
					The command must be available for the batch, i.e. this command must
					translate into an operation (or operations). (Commands like cd, pwd,
					connect, etc are not allowed in the batch, since they don't translate
					into operations). If the new command line isn't valid for some reason
					(syntax error or invalid arguments), edit-batch-line will fail and the
					current command line won't be replaced with the invalid one.					