Changes

Bug 1219: IOUtil.testDirExe: Satisfactory when executed, more debug
options
IOUtil.testDirExe():
 - Satisfactory when executed
   Failure to execute produce an IOException right at
ProcessBuilder.start().
   Hence we can allow an unexpected process exit value,
   since we only want to learn whether executable files are allowed.
  - More debug options
   DEBUG_EXE:          'jogamp.debug.IOUtil.Exe'
   DEBUG_EXE_NOSTREAM: 'jogamp.debug.IOUtil.Exe.NoStream'
    - if DEBUG_EXE
     - a pre-existing 'jogamp_exe_tst'+<SUFFIX> will be used as-is.
      - the test-exe will not be deleted
      - StreamMonitor is being used to dump stdout/stderr
       if !DEBUG_EXE_NOSTREAM.

Bug 1219: Fix IOUtil.StreamMonitor EOS handling
- Make StreamMonitor a daemon thread, i.e. not hindering VM from exit
- Earmark each InputStream's EOS state
 and only attempt to readByte if !eos
- End loop and hence the thread if all InputStream
 have reached EOS.
- Don't close the InputStream.
 Closing the InputStream is expected to be done
 by the owner, otherwise no EOS could even be reached!
- Flush the output PrintStream at thread exit