Started developing a unit test module

Folder per module in test/.  Header only tests with one actual main
file to implement a program that runs them.

Makefile runs the test and provides some eye candy to show if the test
succeeded or failed.  The tests, on the other hand, will show success
or failure for each of them.

test/.dir-locals.el

@@ -0,0 +1,8 @@
+;;; Directory Local Variables         -*- no-byte-compile: t; -*-
+;;; For more information see (info "(emacs) Directory Variables")
+
+((nil    . ((+license/license-choice            . "GPLv2")))
+ (c-mode . ((flycheck-gcc-include-path          . (".." "../.."))
+            (flycheck-clang-include-path        . (".." "../.."))
+            (company-clang-arguments            . ("-I.." "-I../../"))
+            (eval                               . (clang-format-mode t)))))