Drop support for py3.6 and py2.5

Those are too crazy..

Honestly, supporting py2.6 is crazy as well, but I will drop support
only as soon as I see specific need to do it.

(not enforcing >= py2.5 in the setup file for now, it might still work.)

.travis.yml

@@ -2,9 +2,9 @@ language: python
 python:
     - "2.6"
     - "2.7"
-    - "3.2"
     - "3.3"
     - "3.4"
+    - "3.5"
 
 install:
     - pip install -e git+git://github.com/tomerfiliba/plumbum.git#egg=plumbum

setup.py

@@ -51,14 +51,13 @@
         "Intended Audience :: System Administrators",
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
-        "Programming Language :: Python :: 2.5",
         "Programming Language :: Python :: 2.6",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.0",
-        "Programming Language :: Python :: 3.1",
-        "Programming Language :: Python :: 3.2",
         "Programming Language :: Python :: 3.3",
+        "Programming Language :: Python :: 3.4",
+        "Programming Language :: Python :: 3.5",
+        "Programming Language :: Python :: 3.6",
         "Topic :: Internet",
         "Topic :: Software Development :: Libraries :: Python Modules",
         "Topic :: Software Development :: Object Brokering",