Update README.md (#391)

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+++ b/README.md
@@ -9,7 +9,7 @@
 
 * Mac OS X. Tested on 10.11 El Capitan, 10.12 Sierra, iOS 9.0 and iOS 10.0
 * You need to have a valid iOS Development certificate installed.
-* Xcode 7 or greater should be installed (**NOT** Command Line Tools!)
+* Xcode 7 or greater should be installed (**NOT** just Command Line Tools!)
 
 ## Roadmap