Add the second exercise.
Remove a leftover comment from exercise 1.1
Merge pull request #11 from solventz/probability-and-computing-1.2

Add the second exercise.
Begin with a description of the filename.
Merge pull request #12 from solventz/see-about-merging-p-and-c-describ

Begin with a description of the filename.
Clean up p-and-c 1.1