add single quotes around package names in description file as per Uwe

DESCRIPTION

@@ -18,9 +18,9 @@ Authors@R: c(
     person("Moritz", "Marbach", role = "aut", email = "[email protected]", comment = "ggnet, ggnet2"),
     person("Edwin", "Thoen", role = "aut", email = "[email protected]", comment = "ggsurv"),
     person("Amos", "Elberg", role = "aut", email = "[email protected]", comment = "ggnetworkmap"))
-Description: The R package \href{http://docs.ggplot2.org/current/}{ggplot2}
-    is a plotting system based on the grammar of graphics. \href{https://
-    ggobi.github.io/ggally}{GGally} extends ggplot2 by adding several functions to
+Description: The R package '\href{http://docs.ggplot2.org/current/}{ggplot2}'
+    is a plotting system based on the grammar of graphics. '\href{https://
+    ggobi.github.io/ggally}{GGally}' extends 'ggplot2' by adding several functions to
     reduce the complexity of combining geoms with transformed data. Some of these
     functions include a pairwise plot matrix, a scatterplot plot matrix, a parallel
     coordinates plot, a survival plot, and several functions to plot networks.