Disclaim compatibility with Python 2.6.

Author: pavoljuhas

setup.py

@@ -95,7 +95,6 @@ def getversioncfg():
             'License :: OSI Approved :: BSD License',
             'Operating System :: MacOS',
             'Operating System :: POSIX',
-            'Programming Language :: Python :: 2.6',
             'Programming Language :: Python :: 2.7',
             'Topic :: Scientific/Engineering :: Chemistry',
             'Topic :: Scientific/Engineering :: Physics',