Remove support for python2.6

Python2.6 has been last release 9 years ago, I do not intend to
maintain support for python2.6 anymore.

Signed-off-by: Arthur Gautier <baloo@gandi.net>

Author: Arthur Gautier

.travis.yml

@@ -1,7 +1,6 @@
 dist: trusty
 language: python
 python:
-  - "2.6"
   - "2.7"
   - "3.3"
   - "3.4"

README.md

@@ -44,7 +44,7 @@ Project status
 
 The project is test with:
 * MySQL 5.5, 5.6 and 5.7
-* Python >= 2.6
+* Python >= 2.7
 * Python 3.3, 3.4, 3.5 and 3.6 (3.2 is not supported)
 * PyPy (really faster than the standard Python interpreter)