Fixes markup, adds Rmarkdown and iPython NB docs for exercise.

README.md

@@ -5,9 +5,10 @@
     - `gapminder-7080.csv`: 1970s and 1980s
     - `gapminder-90plus.csv`: 1990s onwards
 
-- **Important note about `gapminder-5060.csv`:
+- **Important note** about `gapminder-5060.csv`:
     - The dataset has been altered to add a "data error".
     - Life expectancy for Canada in the year 1967 is coded
     as `999999`, it should actually be `69.96`.
     - For details see [intro-01-slides.Rmd](https://github.com/Reproducible-Science-Curriculum/rr-intro/blob/master/intro-01-slides.Rmd).
-    - `gapminder-5060_original.csv` contains the correct data.
+    - `gapminder-5060_original.csv` contains the correct data.
+- `rr-intro-exercise.Rmd` and `rr-intro-exercise.ipynb`: Rmarkdown and iPython Notebook versions for the first exercise.