Distributions -> Distribution Packages for titles

"Python Distributions" already refers to things like ActivePython, Anaconda, EPD, Canopy and Python(x, y), so switching to the less ambiguous "Distribution Packages" for these section titles.

Author: ncoghlan

source/installing.rst

@@ -15,8 +15,8 @@ This tutorial covers the basics of how to install Python :term:`packages
 
 .. _installing_setup:
 
-Setup for Installing Distributions
-==================================
+Setup for Installing Distribution Packages
+==========================================
 
 This section describes the steps to follow before installing other
 Python packages.  You will want to install :ref:`pip` and
@@ -116,8 +116,8 @@ For more information, see the `virtualenv <http://virtualenv.pypa.io>`_ docs or
 the `pyvenv`_ docs.
 
 
-Installing Python Distributions
-===============================
+Installing Python Distribution Packages
+=======================================
 
 :ref:`pip` is the recommended installer, and supports various requirement forms
 and options.  For details, see the `pip docs