Update the README with proper first-time installation instructions.

README.md

@@ -7,9 +7,9 @@ Only the php vendors are not included.
 
 ## Run locally for fast development
 
-	composer install
+Install dependencies:
 
-http://getcomposer.org/
+	bin/grav install
 
 Then try out
 
@@ -17,11 +17,6 @@ Then try out
 
 to troubleshoot.
 
-Perhaps
-
-	bin/grav install
-
-
 Add the courses from the other repository
 
 	bin/clone_courses.sh