Added explanation for the binary blob in runtests.py

_pytest/standalonetemplate.py

@@ -1,5 +1,24 @@
 #! /usr/bin/env python
 
+# Hi There!
+# You may be wondering what this giant blob of binary data here is, you might
+# even be worried that we're up to something nefarious (good for you for being
+# paranoid!). This is a base64 encoding of a zip file, this zip file contains
+# a fully functional basic pytest script.
+#
+# Pytest is a thing that tests packages, pytest itself is a package that some-
+# one might want to install, especially if they're looking to run tests inside
+# some package they want to install. Pytest has a lot of code to collect and
+# execute tests, and other such sort of "tribal knowledge" that has been en-
+# coded in its code base. Because of this we basically include a basic copy
+# of pytest inside this blob. We do this  because it let's you as a maintainer
+# or application developer who wants people who don't deal with python much to
+# easily run tests without installing the complete pytest package.
+#
+# If you're wondering how this is created: you can create it yourself if you
+# have a complete pytest installation by using this command on the command-
+# line: ``py.test --genscript=runtests.py``.
+
 sources = """
 @SOURCES@"""