Add code for doxygen deployment

The @example doxygen section was added back to grrlib.h.
It was deleted by mistake in commit 4007b45af1.

.travis.yml

@@ -10,6 +10,11 @@ env:
     - DEVKITPRO=$HOME/devkitPro
     - DEVKITPPC=${DEVKITPRO}/devkitPPC
 
+addons:
+  apt:
+    packages:
+      - doxygen
+
 cache:
   directories:
     - ${DEVKITPRO}
@@ -24,3 +29,12 @@ script:
   - (cd GRRLIB && sudo -E make clean all install)
   - (cd examples && make)
   - (cd GRRLIB && sudo -E make PLATFORM=cube clean all)
+  - doxygen grrlib.doxygen
+
+deploy:
+  provider: pages
+  skip_cleanup: true
+  local_dir: $TRAVIS_BUILD_DIR/doc
+  github_token: $GITHUB_TOKEN
+  on:
+    branch: master

GRRLIB/GRRLIB/grrlib.h

@@ -227,4 +227,9 @@ GRR_EXTERN  u32         fb       GRR_INIT(0);
  *
  * @section Licence
  * See the [LICENCE](LICENCE.md) file for licence rights and limitations (MIT).
+ *
+ * @example template/source/main.c
+ * This example shows the minimum code required to use GRRLIB.
+ * It could be used as a template to start a new project.
+ * More elaborate examples can be found inside the \e examples folder.
  */