Add linux shell script test for the clang compiler.
Remove werror from clang/linux build script.

Until we can determine that we are building cleanly and can remove the
warnings.
Strip cflags and coverage flags.

Done to determine reason(s) for llvm undefined symbols.
Have Tuvok submodule track the 'travis' branch.

Necessary for running travis CI tests.
Readd -D_GLIBCXX_DEBUG to project.

Attempting to fix errors in tests.
Track tuvok master branch by default.
Merge branch 'master' into travis