Fix typo in and reformat OS X Installer ReadMe

Mac/BuildScript/resources/ReadMe.txt

@@ -36,18 +36,19 @@ New Installation Options and Defaults
 The Python installer now includes an option to automatically install
 or upgrade pip, a tool for installing and managing Python packages.
 This option is enabled by default and no Internet access is required.
-If you do want the installer to do this, select the "Customize" option
-at the "Installation Type" step and uncheck the "Install or ugprade
-pip" option.
+If you do not want the installer to do this, select the "Customize"
+option at the "Installation Type" step and uncheck the "Install or
+ugprade pip" option.
 
 To make it easier to use scripts installed by third-party Python
 packages, with pip or by other means, the "Shell profile updater"
 option is now enabled by default, as has been the case with Python
 2.7.x installers. You can also turn this option off by selecting
-"Customize" and unchecking the "Shell profile updater" option. You can
-also update your shell profile later by launching the "Update Shell
-Profile" command found in the /Applications/Python $VERSION folder. You may
-need to start a new terminal window for the changes to take effect.
+"Customize" and unchecking the "Shell profile updater" option. You
+can also update your shell profile later by launching the "Update
+Shell Profile" command found in the /Applications/Python $VERSION
+folder.  You may need to start a new terminal window for the
+changes to take effect.
 
 Python.org Python $VERSION and 2.7.x versions can both be installed and
 will not conflict. Command names for Python 3 contain a 3 in them,