docs: Add docs/ folder with in depth topics as well as DoxygenLayout.xml file

* C headers now have @briefs and include examples
* Examples have altered 'Interesting' Sections

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

docs/galileorevd.md

@@ -0,0 +1,10 @@
+Galileo Rev D                            {#galileorevd}
+=============
+
+Galileo is a microcontroller board based on the Intel® Quark SoC X1000
+Application Processor, a 32-bit Intel Pentium-class system on a chip.
+
+The rev D board has the following limitations in libmaa:
+
+- gpio register access via /dev/uio is limited to pin2 and 3
+- gpio interupts will only work on GPIO_EDGE_BOTH