Build: Support common+sense+wilzor API libs; Move xcbXorg into commonLibs

xcbXorg is a connection manager lib that'll be used in common by all of
the xcb API frontends: xcbMouse, xcbWindow and xcbKeyboard. We moved
it into commonLibs to make it make more sense.

We also cleaned up the M4 scripting around AC_ARG_VAR-ing new common
libs as well as sense/wilzor libs.

commonLibs/xcbXorg/xcbXorg.h

@@ -0,0 +1,22 @@
+#ifndef X11_XCB_API_H
+#define X11_XCB_API_H
+
+#include <string>
+#include <vector>
+#include <memory>
+#include <user/senseApiDesc.h>
+
+class Xcb_XorgApi
+{
+public:
+    Xcb_XorgApi(const std::string& _displayName)
+    :   displayName(_displayName)
+    {}
+
+    ~Xcb_XorgApi() = default;
+
+private:
+    std::string displayName;
+};
+
+#endif // X11_XCB_API_H