New c-mode Doxygen function documentation using Javadoc style tags. (#264)

* New c-mode Doxygen function documentation using Javadoc style tags.

* Removed double space from doc block.

* Moved alternate c/c++ function documentation block from c-mode to
c-lang-common so that the snippet will be available for both c & c++
programs.

* Reformatted c function Doxygen documentation block. Added @details
section.

* Changed C Doxygen function block trigger to doxy to make it easier to
use. Added new nasm Doxygen function block document snippet.

Author: dpitic

snippets/c-lang-common/function_doxygen_doc

@@ -0,0 +1,15 @@
+# -*- mode: snippet -*-
+# contributor: Dan Pitic <[email protected]>
+# name: Function Doxygen Doc
+# key: doxy
+# group: doxygen
+# --
+/**
+ * @brief    ${1:function description}
+ *
+ * @details  ${2:detailed description}
+ *
+ * @param    ${3:param}
+ *
+ * @return   ${4:return type}
+ */

snippets/nasm-mode/function_doc

@@ -0,0 +1,15 @@
+# -*- mode: snippet -*-
+#name : Assembly Function Doc
+#key : doxy
+#group : doxygen
+#contributor : Dan Pitic <[email protected]>
+# --
+;;
+;; @brief      ${1:function description}
+;;
+;; @details    ${2:detailed description}
+;;
+;; @param      ${3:param}
+;;
+;; @return     ${4:return}
+;;