Increment version number

[skip ci]
diff --git a/DESCRIPTION b/DESCRIPTION
index 94eb48b..0cd39b7 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Type: Package
 Package: revealjs
 Title: R Markdown Format for 'reveal.js' Presentations
-Version: 0.9.1
+Version: 0.9.1.9000
 Date: 2017-03-13
 Authors@R: 
     c(person(given = "Hakim",
diff --git a/NEWS.md b/NEWS.md
index 2bbacf7..b5ad02b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,5 @@
+# revealjs (development version)
+
 # revealjs 0.9
 
 - Add support for the menu plugin