Add "python -m simtk.testInstallation" to .travis.yml

.travis.yml

@@ -21,6 +21,8 @@ script:
   - make -j2
   - make -j2 install
   - sudo make PythonInstall
+  - # Run the testInstallation script
+  - python -m simtk.testInstallation
   - # run all of the tests
   - ctest -j2 -V
   - # get a list of all of the failed tests into this stupid ctest format