update from dtk-template - clangd :) (#66)

* update from dtk-template and start work towards using clangd

* include <a> -> "a"

* Update build.yml

* remove/add non-trivial class in union warning

src/m/m_angle.cpp

@@ -1,4 +1,4 @@
-#include <m/m_angle.h>
+#include "m/m_angle.h"
 
 /** 80575c08 */
 mAng3_c mAng3_c::Zero = mAng3_c::mAng3_c(0, 0, 0);