Drop python 3.3 and add 3.7

3.3.x has reached end of life

Author: isuruf

.travis.yml

@@ -33,7 +33,7 @@ env:
   # Release builds:
   - PYTHON_VERSION="2.7" BUILD_SHARED_LIBS="yes"
   - PYTHON_VERSION="2.7" WITH_MPFR="yes" INTEGER_CLASS="gmpxx" WITH_NUMPY="no"
-  - PYTHON_VERSION="3.3" WITH_MPC="yes"
+  - PYTHON_VERSION="3.7" WITH_MPC="yes"
   - PYTHON_VERSION="3.4" WITH_MPFR="yes"
   - PYTHON_VERSION="3.5" WITH_MPC="yes"
   - PYTHON_VERSION="3.6" WITH_MPC="yes" INTEGER_CLASS="flint" WITH_FLINT="yes"

setup.py

@@ -240,8 +240,9 @@ def finalize_options(self):
         'Topic :: Scientific/Engineering :: Mathematics',
         'Topic :: Scientific/Engineering :: Physics',
         'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         ]
       )