Small cosmetic change to the README.md.

README.md

@@ -2,10 +2,10 @@
 
 This repository contains a collection of statistical tools for the
 analysis of time series data. It is split into two subpackages:
-- metrics: collection of statistics and metrics to calculate on
-           **hourly** time series data (some specific to ozone
-           measurements)
-- trends: calculate quantile regression on time series data
+- **metrics**: collection of statistics and metrics to calculate on
+               **hourly** time series data (some specific to ozone
+               measurements)
+- **trends**: calculate quantile regression on time series data
 
 ## Installation