Modify read_write test to allow specification of rank to read stdin.
IOF now validated to work for arbitrary rank as stdin target. Not validate to work for multiple simultaneous ranks reading stdin (untested).
This commit was SVN r19804.
1. remove some stale files that were overlooked in original commit
2. add a test program and data to stress iof for stdin
3. cleanup a debug statement that caused memory corruption when reading large files
4. some minor cleanups to correctly handle xon/xoff scenarios
This commit was SVN r19792.