Add additional code analysis tools to CI

Related to #3 (closed).

/cc @dion @ximinity

• Decide which tools to use
• Implement tools in docker image
  • Maybe multiple images? Don't want to bloat the main image too much
• Add tools and stuffs to gitlab-ci.yml

A list of some stuff I found:

• https://bitbucket.org/verateam/vera/wiki/Home
• http://clang-analyzer.llvm.org/ (implemented)
• http://forge.ispras.ru/projects/blast
• http://frama-c.com/
• http://splint.org/
• http://coccinelle.lip6.fr/
• http://www.dwheeler.com/flawfinder/
• http://www.spinroot.com/uno/
• http://smatch.sourceforge.net/

There are probably more, but only floss and self-hostable / runnable / scriptable is allowed obviously.