Changes in CCMMR version 0.2

    + Added new option to guarantee a connected weight matrix in
      sparse_weights().

    + Replaced some inefficient parts of the C++ code.

    + Added several options to monitor the algorithm's performance during
      minimization. Monitoring can be turned on using the relevant arguments of
      convex_clusterpath(). Data gathered while monitoring is part of the
      output of convex_clusterpath().
