coroutine 1/2 done
Final review of basics.

I finally finished reviewing the first 10 chapters. Now while, I believed
the rest of the chapters were going to be pretty straight forward, the damn
exercises are really intense. I been coding a for a while, and some of them I
just had no idea how to go about them. So if you see an answer missing, it's
cause I couldn't figure out how to really solve it.

On branch master
Changes to committed:
      new file:   10.1.lua
      new file:   10.3.lua
      new file:   8queen_puzzle.lua
      new file:   markov_chain.lua
      new file:   most_frequent_word.lua