Add link to poker-player-R
Merge pull request #66 from lean-poker/poker-player-R

Add link to poker-player-R
Fix typos and (where it helps readability) tweak grammar

My favourite typo, by far, is bellow. Although it is also a word, it
doesn't really fit the poker context! :-)
Merge pull request #67 from sinisterstuf/typos

Fix typos in README and (where it helps readability) tweak grammar