Added maxflow algorithm.

Added implementation by Kolmogorov of a graph structure and an algorithm to
compute the maxflow on it.
This is used in order to find the exact minimization of the decomposition.

     * src/maxflow/block.h: Here.
     * src/maxflow/graph.cpp: Here.
     * src/maxflow/graph.h: Here.
     * src/maxflow/maxflow.cpp: Here.
Add support for alpha and gamma look-up tables in the minimizer.

    * src/TVL0DecompositionMinimizer.cc: Here.
    * src/TVL0DecompositionMinimizer.hh: Here.
    * src/main.cc: Dummy values in order to compile.
Started construction of graph.

	* src/TVL0DecompositionMinimizer.cc: Here.
Implements the graph construction

	   * src/TVL0DecompositionMinimizer.cc: Here.
Fix typo in doxygen comments.

    * src/TVL0DecompositionMinimizer.hh: Here.
Added a class to compute the data term.

For now, only con compute quadratic data term.
TVL0DecompositionMinimizer is now templated by this class and use it in the
computation.

	* CMakeLists.txt: Remove TVL0DecompositionMinimizer.cc (no longer exist)
	* src/QuadraticDataTerm.hh: New.
	* src/QuadraticDataTerm.hxx: New.
	* src/TVL0DecompositionMinimizer.hxx: was .cc before.
	* src/TVL0DecompositionMinimizer.hh: Now use the template class.
	* src/main.cc: Use the new class.
Fix bugs to compile on linux gcc 4.6

    * src/Args.cc: Include cstring.
    * src/QuadraticDataTerm.hh: fix typo.
Graph construction ok, but still buggy...

Should use more templates to enforce type.

      * src/TVL0DecompositionMinimizer.hh: Changed to unsigned.
      * src/TVL0DecompositionMinimizer.hxx: Same.
      * src/main.cc: comply to changes above.