setup: Shorten list of supported python versions

Reduces the list of supported python versions to 2 and 3 in the
manifest. Although it works with a lot of dot-releases, the list just
grows too large.

setup.py

@@ -63,13 +63,7 @@ def find_meta(meta, *path):
 			"License :: OSI Approved :: GNU General Public License v2 (GPLv2)",
 			"Programming Language :: Python",
 			"Programming Language :: Python :: 2",
-			"Programming Language :: Python :: 2.7",
 			"Programming Language :: Python :: 3",
-			"Programming Language :: Python :: 3.4",
-			"Programming Language :: Python :: 3.5",
-			"Programming Language :: Python :: 3.6",
-			"Programming Language :: Python :: 3.7",
-			"Programming Language :: Python :: 3.8",
 			'Topic :: Scientific/Engineering :: Physics',
 			'Topic :: Utilities',
 		],