allow failure for python2.6 in travis and update minimum supported python version to 2.7, as well as adding an annoying deprecation warning

.travis.yml

@@ -2,7 +2,6 @@ language: python
 
 matrix:
   include:
-  - python: '2.6'
   - python: '2.7'
   - python: '3.3'
   - python: '3.4'
@@ -11,6 +10,7 @@ matrix:
   - python: '3.6'
   - python: '3.7-dev'
   allow_failures:
+  - python: '2.6'
   - python: '3.7-dev'
 
 before_install:

docs/install.rst

@@ -146,12 +146,12 @@ To install Streamlink from source you will need these dependencies.
 ==================================== ===========================================
 Name                                 Notes
 ==================================== ===========================================
-`Python`_                            At least version **2.6** or **3.3**.
+`Python`_                            At least version **2.7** or **3.3**.
 `python-setuptools`_
 
 **Automatically installed by the setup script**
 --------------------------------------------------------------------------------
-`python-argparse`_                   Only needed on Python **2.6**.
+`python-argparse`_                   Only needed on Python versions older than **2.7**.
 `python-futures`_                    Only needed on Python **2.x**.
 `python-requests`_                   At least version **1.0**.
 `python-singledispatch`_             Only needed on Python versions older than **3.4**.

setup.py

@@ -65,7 +65,6 @@ setup(name="streamlink",
                    "Environment :: Console",
                    "Operating System :: POSIX",
                    "Operating System :: Microsoft :: Windows",
-                   "Programming Language :: Python :: 2.6",
                    "Programming Language :: Python :: 2.7",
                    "Programming Language :: Python :: 3.3",
                    "Programming Language :: Python :: 3.4",

src/streamlink/__init__.py

@@ -9,8 +9,18 @@ An API is also provided that allows direct access to stream data.
 Full documentation is available at https://streamlink.github.io.
 
 """
+import warnings
+from sys import version_info
 
 
+if version_info[:2] == (2, 6):
+    warnings.warn(
+        "Python 2.6 is no longer supported by the Python core team, please "
+        "upgrade your Python. A future version of streamlink will drop "
+        "support for Python 2.6",
+        DeprecationWarning
+    )
+
 __title__ = "streamlink"
 __version__ = "0.3.1"
 __license__ = "Simplified BSD"