increment version.

setup.py

 from setuptools import setup
 
 setup(name='solventmapcreator',
-      version='2.5.3',
+      version='2.6.0',
       description='python scripts for generating solvent maps and analysing solvation curves.',
       url='https://bitbucket.org/mdd31/solventmapcreator',
       author='Mark Driver',