Doc comment maintenance

Fixed doc comments issues:

* Fixed mistyped param doc comments (`/**<` is OK, `/** <` is not).

* Put special characters (e.g., pipe, backslash, etc.) in quotes, as they can
  confuse doxygen and it will print lots of various warnings. For the sake of
  completeness and consistent style, also quote some special characters in
  re-bytecode.h

* Added missing `@{`s, removed extra `@}`s.

* Turned `/*` comments to `/**<` doc comments.

Ensured same style for doc groups everywhere:

* Where `\addtogroup`, `@{`, and `@}` doxygen commands are used, the order to be
  followed is: license, `#ifndef` guards (in headers), includes, `\addtogroup`
  and `@{`, main code content, `@}`, `#endif` guards (in headers).

* Multiple `\addtogroup`s or multiple `@}`s should be in the same doc comment.

* First `\addtogroup` should be on the very first line of a doc comment, i.e.,
  `/** \addtogroup`.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

jerry-core/ecma/operations/ecma-eval.c

@@ -28,6 +28,7 @@
  * @{
  *
  * \addtogroup eval eval
+ * @{
  */
 
 /**

jerry-core/ecma/operations/ecma-eval.h

@@ -22,6 +22,7 @@
  * @{
  *
  * \addtogroup eval eval
+ * @{
  */
 
 extern ecma_value_t

jerry-core/ecma/operations/ecma-exceptions.c

@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,9 +23,7 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup exceptions Exceptions
  * @{
  */

jerry-core/ecma/operations/ecma-exceptions.h

@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,9 +21,7 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup exceptions Exceptions
  * @{
  */

jerry-core/ecma/operations/ecma-lex-env.c

@@ -26,14 +26,10 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup lexicalenvironment Lexical environment
  * @{
- */
-
-/**
+ *
  * \addtogroup globallexicalenvironment Global lexical environment
  * @{
  */

jerry-core/ecma/operations/ecma-lex-env.h

@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,14 +22,10 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup lexicalenvironment Lexical environment
  * @{
- */
-
-/**
+ *
  * \addtogroup globallexicalenvironment Global lexical environment
  * @{
  */

jerry-core/ecma/operations/ecma-number-arithmetic.c

@@ -19,9 +19,7 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup numberarithmetic ECMA number arithmetic operations
  * @{
  */

jerry-core/ecma/operations/ecma-number-arithmetic.h

@@ -20,9 +20,7 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup numberarithmetic ECMA number arithmetic operations
  * @{
  */

jerry-core/ecma/operations/ecma-objects-arguments.c

@@ -14,13 +14,6 @@
  * limitations under the License.
  */
 
-/** \addtogroup ecma ECMA
- * @{
- *
- * \addtogroup ecmafunctionobject ECMA Function object related routines
- * @{
- */
-
 #include "ecma-alloc.h"
 #include "ecma-builtin-helpers.h"
 #include "ecma-builtins.h"
@@ -35,6 +28,13 @@
 #include "ecma-try-catch-macro.h"
 #include "jrt.h"
 
+/** \addtogroup ecma ECMA
+ * @{
+ *
+ * \addtogroup ecmafunctionobject ECMA Function object related routines
+ * @{
+ */
+
 /**
  * Arguments object creation operation.
  *

jerry-core/ecma/operations/ecma-reference.c

@@ -23,9 +23,7 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup references ECMA-Reference
  * @{
  */

jerry-core/ecma/operations/ecma-reference.h

@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,9 +21,7 @@
 
 /** \addtogroup ecma ECMA
  * @{
- */
-
-/**
+ *
  * \addtogroup references ECMA-Reference
  * @{
  */