Merge pull request CamDavidsonPilon#158 from georgemarrows/master

Typo + code fix to Poisson example in chapter 1

Author: CamDavidsonPilon

Chapter1_Introduction/Chapter1_Introduction.ipynb

@@ -17,7 +17,7 @@
       "========\n",
       "\n",
       "#####Version 0.1\n",
-      "Welcome to *Bayesian Methods for Hackers*. The full Github repository is available at [github/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers](https://github.com/CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers). The other chapters can be found on the projects [homepage](camdavidsonpilon.github.io/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers/). We hope you enjoy the book, and we encourage any contributions!"
+      "Welcome to *Bayesian Methods for Hackers*. The full Github repository is available at [github/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers](https://github.com/CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers). The other chapters can be found on the project's [homepage](camdavidsonpilon.github.io/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers/). We hope you enjoy the book, and we encourage any contributions!"
      ]
     },
     {
@@ -427,6 +427,7 @@
       "a = np.arange(16)\n",
       "poi = stats.poisson\n",
       "lambda_ = [1.5, 4.25]\n",
+      "colours = [\"#348ABD\", \"#A60628\"]\n",
       "\n",
       "plt.bar(a, poi.pmf(a, lambda_[0]), color=colours[0],\n",
       "        label=\"$\\lambda = %.1f$\" % lambda_[0], alpha=0.60,\n",