Make Python .gitignore directory entries match only directories.

This commit also alphabetizes the distribution/packaging section after
separating the directory entries from the file entries.  I left alone
a few entries that I'm not sure about (i.e. *.egg and the
"Mr Developer" section).

Python.gitignore

@@ -1,31 +1,31 @@
 # Byte-compiled / optimized / DLL files
+__pycache__/
 *.py[cod]
 
 # C extensions
 *.so
 
-# Packages
+# Distribution / packaging
-*.egg
+bin/
-*.egg-info
+build/
-dist
+develop-eggs/
-build
+dist/
-eggs
+eggs/
-parts
+lib/
-bin
+lib64/
-var
+parts/
-sdist
+sdist/
-develop-eggs
+var/
+*.egg-info/
 .installed.cfg
-lib
+*.egg
-lib64
-__pycache__
 
 # Installer logs
 pip-log.txt
 
 # Unit test / coverage reports
+.tox/
 .coverage
-.tox
 nosetests.xml
 
 # Translations