Add comment about the difference between full and reduced assets.

Author: ntoll

README.rst

@@ -7,6 +7,13 @@ It contains the assets needed to automatically build Python 3.6 for Mac OSX
 such that the resulting version of Python is a stand-alone runtime to be
 included in the OSX based installable for Mu.
 
+There are two versions of each release:
+
+* Full - where everything is included.
+* Reduced - where man pages, tests, IDLE and ensurepip are removed.
+
+The reduced version is the one included in the OSX installer for Mu.
+
 IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
 DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF
 THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN