Fix return value of run_tests

[GoogleCodeExporter]

The way run_tests is currently implemented leads to problems with the exit 
status of the test run.

The line

return sea_tests_failed == 0;

returns 1 if the comparison succeeds. However, the exit status 1 stands for 
failure.

I would propose the following fix:

if (sea_tests_failed == 0) {
  return 0;
else {
  return -1;
}

Original issue reported on code.google.com by [email protected] on 17 Aug 2014 at 4:56

[keithn]

see #13