When we find includes, make sure they're valid.
Squashed 'third_party/websocketpp/' content from commit e7ce038

git-subtree-dir: third_party/websocketpp
git-subtree-split: e7ce038207e2c1727a490421afbbe8e41b242318
Merge commit 'c361be979f0d34ca12a9db675c8602e46f8de6e5' as 'third_party/websocketpp'
Add the websocketpp library as an include / link against it by default

This makes it so we can utilize it simply inside our codebase. This
doesn't udpate the overriden configs in debug/release.starsha. Those
should be updated when needed.
Merge pull request #30 from cmaloney/websocketpp

Websocketpp
Obey the ODR Rule - the same class shouldn't exist twice (even in CC files)

Should Fix #31
Merge pull request #32 from cmaloney/issue-31

Obey the ODR Rule - the same class shouldn't exist twice (even in CC files)
Fix <mpl/typical.test> after I broke it only partly removing <mpl/sort.h>