Script documentation generation and UML support (#992)

Documentation is now generated by invoking a shell script
which takes care of all the plumbing.
There is now also support of inlineing PlantUML syntax with
Doxygen. This inlining takes the form of
@startuml{imagename.png}
'PlantUML specific syntax'
@enduml
The inlineing can be made in C syntax comment blocks.
Doxygen will then include the generated UML diagram when
rendering the HTML documentation.
All generated images will be placed under Documentation/img
which is the default search path for Doxygen.

Documentation/doxygen.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+## Invoke from project root, e.g Documentation/doxygen.sh
+
+# Generate doxygen file for Raspberry Pi configure command
+echo -e "/**\n * @defgroup RaspberryPiGateway Raspberry Pi Gateway\n * @ingroup MyConfigGrp\n * @brief Configuration options for the Raspberry Pi Gateway\n@{\n@verbatim" > configure.h
+				grep -A999 '<<EOF' configure | grep -B999 EOF | grep -v 'EOF' >> configure.h
+				echo -e "@endverbatim\n@}*/\n" >> configure.h
+
+# Generate version information
+export PROJECTNUMBER=$(
+	if [[ $(git rev-parse --abbrev-ref HEAD) == "master" ]]; then
+		git describe --tags ;
+	else
+		git rev-parse --short HEAD ;
+	fi
+)
+
+# Generate any UML diagrams in the code tree that has the proper tags
+export PLANTUML_JAR_PATH=Documentation/plantuml.jar
+java -Djava.awt.headless=true -jar $PLANTUML_JAR_PATH -failfast2 -nbthread auto -o "$PWD/Documentation/img" "./**.(c|cpp|dox|h|hpp|ino)"
+
+# Launch Doxygen (assumed to be in the PATH)
+doxygen
+
+# Show any warnings created
+cat doxygen.log
+
+# Clean up autogenerated (temporary) artifacts
+rm configure.h