Imported the AX_CXX_COMPILE_STDCXX_11 macro from the Autoconf Archive.

Source: http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
Imported two AX_BOOST_* M4 macros from the Autoconf Archive.

Source: http://www.gnu.org/software/autoconf-archive/
Imported a Doxygen configuration file template generated with:

    $ doxygen -g doc/doxygen/Doxyfile
Customized the Doxygen configuration file.
Imported a DOAP file for the project.