issue_6517: Emoji support

Added issue support for the different output types.

- Sources of the emoji
  - based on the Unicode definition v11.0:
    - https://unicode.org/emoji/charts/full-emoji-list.html
    - http://www.unicode.org/emoji/charts/full-emoji-modifiers.html
  - github definition list:
    - https://api.github.com/emojis

- Input of emoji: :<test>: with the restriction that direct after the opening colon and direct before the closing colon no space is allowed
  - doctokinizer.l, adding detection of emoji and new command `\:`
  - doktokinizer.h, adding "word" type  TK_EMOJI
  - docparser.* handling of new "word" type TK_EMOJI (analogous to HTML Entities), handling of new command `\:`
  - cmdmapper,cpp, cmdmapper.h, adding new command `\:`
  - htmlentity.cpp, adding new definition required for new command `\:`

- Emoji
  - emoji.cpp, emoji.h, class for handling emoji analogous to HTML Entities, including small directions on how to update the code when a new emoji is defined. Not everything is converted to lowercase for comparison and accents are removed.
  - doxygen.cpp possibility to create list of supported emoji

- handling emoji for output types (analogous to HTML Entities), see documentation for different output types
  - docparser.h, *docvisitor.*
  - rtfdocvisitor.* converting output to UTF-16 (based on http://scruss.com/blog/2017/03/12/in-the-unlikely-event-you-need-to-represent-emoji-in-rtf-using-perl/)
  - latexdocvisitor.*, handling arguments for emoji in output (see also latexgen.cpp for meaning of the arguments of doxygenemoji).
  - latexgen.cpp, adding new latex command for doxygen (doxygenemoji) and prevent too many open file (code before documentclass)
  - config.xml, definition of `LATEX_EMOJI_DIRECTORY` with path to images required for LaTeX output

- Documentation:
   - emojisup.doc, user description
   - commands.doc, description of new command `\:`
   - index.doc, reference to emoji chapter
   - xmlcmds.doc, adjust reference to next chapter as a new chapter is added
   - Doxyfile*, adding emoji chapter

Build system
  - CMakeLists.txt adding new files

1 files changed, 33 insertions, 0 deletions

diff --git a/src/doxygen.cpp b/src/doxygen.cpp
index 9d8a914..cd2cc8d 100644
--- a/src/doxygen.cpp
+++ b/src/doxygen.cpp
@@ -103,6 +103,7 @@
 #include "settings.h"
 #include "context.h"
 #include "fileparser.h"
+#include "emoji.h"
 
 // provided by the generated file resources.cpp
 extern void initResources();
@@ -10029,6 +10030,9 @@ static void usage(const char *name)
   msg("    RTF:   %s -e rtf extensionsFile\n\n",name);
   msg("7) Use doxygen to compare the used configuration file with the template configuration file\n");
   msg("    %s -x [configFile]\n\n",name);
+  msg("8) Use doxygen to show a list of build in emoji.\n");
+  msg("    %s -f emoji outputFileName\n\n",name);
+  msg("    If - is used for outputFileName doxygen will write to standard output.\n\n");
   msg("If -s is specified the comments of the configuration items in the config file will be omitted.\n");
   msg("If configName is omitted `Doxyfile' will be used as a default.\n\n");
   msg("-v print version string\n");
@@ -10229,6 +10233,7 @@ void readConfiguration(int argc, char **argv)
   const char *layoutName=0;
   const char *debugLabel;
   const char *formatName;
+  const char *listName;
   bool genConfig=FALSE;
   bool shortList=FALSE;
   bool diffList=FALSE;
@@ -10306,6 +10311,34 @@ void readConfiguration(int argc, char **argv)
         cleanUpDoxygen();
         exit(1);
         break;
+      case 'f':
+        listName=getArg(argc,argv,optind);
+        if (!listName)
+        {
+          err("option \"-f\" is missing list specifier.\n");
+          cleanUpDoxygen();
+          exit(1);
+        }
+        if (qstricmp(listName,"emoji")==0)
+        {
+          if (optind+1>=argc)
+          {
+            err("option \"-f emoji\" is missing an output file name\n");
+            cleanUpDoxygen();
+            exit(1);
+          }
+          QFile f;
+          if (openOutputFile(argv[optind+1],f))
+          {
+            EmojiEntityMapper::instance()->writeEmojiFile(f);
+          }
+          cleanUpDoxygen();
+          exit(0);
+        }
+        err("option \"-f\" has invalid list specifier.\n");
+        cleanUpDoxygen();
+        exit(1);
+        break;
       case 'w':
         formatName=getArg(argc,argv,optind);
         if (!formatName)