Code cleaning and GNU Autotools reworking

I made some changes to the project:

- Small changes in the code so now the server compiles completely cleanly (with both clang and gcc)

- I converted the package to use GNU autotools in a standard way. Now configure takes care of searching for header files, libraries and commands (like openssl). I added a bootstrap file to automate most of the initial tasks (collecting m4 macros and such). This needs to be tested in Mac OS. 

- The build is now out of source by default. 

- Some things we can do now:
 * ./bootstrap.sh --> This creates the build directory with the makefiles and is the place where the executable will be placed
 * We can rerun config with the usual parameters (--prefix, etc)
 * Makefile now provides standard targets (make dist, make clean, make install).

These changes should simplify the task if/when in the future we add more libraries to expand the project to add things like thread pools (libevent/glib for instance).

**TODO**: A standard package adds some files to the distribution like AUTHORS, ChangeLog and COPYING (see automake --add-missing). I think it would be good to add them to the distribution, but the content of those is up to you :)

**Future work**: 
 * Install the sibyl in the Beaglebone and run some tests. 
 * Later, install FreeBSD in the Beaglebone and run the tests again. We should draw some conclusions by then. 
 * My final goal is to add a thread pool  to the sibyl so it scalates automatically with the number of processors and adapt the code to work with capsicum (http://www.freebsd.org/cgi/man.cgi?query=capsicum&sektion=4)