Set Travis CI test timeout to 60s (TriBITSPub#240)

The Travis CI build did not have any timeout set for the tests.  Therefore, if
any one test hung, it would result in a timeout of the overall Travis CI build
and no test results would show up on the TriBITS CDash site.

This change gives what I think is a pretty reasonble default of 60s.

cmake/ctest/travisci/ctest_trusty_serial_debug.cmake

@@ -19,7 +19,7 @@ SET(COMM_TYPE SERIAL)
 SET(BUILD_TYPE DEBUG)
 SET(BUILD_DIR_NAME ${COMM_TYPE}_${BUILD_TYPE}_TravisCI)
 SET(CTEST_SITE TravisCI)
-#SET(CTEST_TEST_TIMEOUT 900)
+SET(CTEST_TEST_TIMEOUT 60)
 
 SET_DEFAULT_AND_FROM_ENV( CTEST_BUILD_FLAGS "-j1 -i" )