doc: include package documentation

doc/doxygen/riot.doxyfile

@@ -759,6 +759,7 @@ INPUT                  = ../../doc.txt \
                          ../../boards \
                          ../../drivers \
                          ../../sys \
+                         ../../pkg \
                          src/ \
                          src/mainpage.md \
                          src/getting-started.md
@@ -836,6 +837,8 @@ EXCLUDE_PATTERNS       = */board/*/tools/* \
                          */cpu/kw2x/include/MKW22D5.h \
                          */cpu/k64f/include/MK64F12.h \
                          */cpu/ezr32wg/include/ezr* \
+                         */pkg/*/*/* \
+                         */pkg/tlsf/patch.txt \
 
 
 # The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names

pkg/doc.txt

@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2015 INRIA
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    pkg Packages
+ * @brief       RIOT supports the integration of external libraries. These
+ *              libraries can be used as BSD-like packages, i.e. they are
+ *              downloaded automatically at compile-time (if needed) and linked
+ *              against RIOT.
+ */