Percolation works. The code gets all the output.

Finally, we get all the necessary output: i) # of clusters; ii) min/max
cluster sizes; iii) cluster size distribution; iv) determination of
percolation.

Next steps:
I. change the testing framework:
   1) introduce the input file with system size, picture file, # of bins,
contact/non-contact, probably BCs;
   2) add the ability to use the default/custom input file name;
   3) stop using the built-in functions like test8() etc.;
II. test intensively;
III. clean the code, port to linux (use boost for shared_ptr), document.