Obsolete doxygen data, build warnings

[dfateyev]

I have got build warnings while testing master branch build:

...
Making all in doc
make[2]: Entering directory '/builddir/build/BUILD/nfdump-master/doc'
/usr/bin/doxygen Doxyfile
touch doxygen-build.stamp
warning: Tag 'TCL_SUBST' at line 237 of file 'Doxyfile' has become obsolete.
         To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: Tag 'CLANG_ASSISTED_PARSING' at line 1038 of file 'Doxyfile' belongs to an option that was not enabled at compile time.
         To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u", or recompile doxygen with this feature enabled.
warning: Tag 'CLANG_OPTIONS' at line 1046 of file 'Doxyfile' belongs to an option that was not enabled at compile time.
         To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u", or recompile doxygen with this feature enabled.
warning: Tag 'COLS_IN_ALPHA_INDEX' at line 1064 of file 'Doxyfile' has become obsolete.
         To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: Tag 'PERL_PATH' at line 2129 of file 'Doxyfile' has become obsolete.
         To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: Tag 'MSCGEN_PATH' at line 2151 of file 'Doxyfile' has become obsolete.
         To avoid this warning please remove this line from your configuration file or upgrade it using "doxygen -u"
warning: argument 'a4wide' for option PAPER_TYPE is not a valid enum value
Using the default: a4!
...

[phaag]

Fixed in master branch.
Thanks!