Python 3.3 isn't supported anymore.

This is because Python 3.4 implements the pickle protocol version 4, which adds
support for pickleing bound methods. Unfortunately, botogram needs them to be
pickled, and so it can't work on Python 3.3 and below.

.travis.yml

@@ -1,6 +1,5 @@
 language: python
 python:
-- "3.3"
 - "3.4"
 - "3.5.0b3"
 

README.md

@@ -26,11 +26,14 @@ if __name__ == "__main__":
 
 You can find the documentation at [botogram.pietroalbini.io][2].
 
+**Supported Python versions**: 3.4, 3.5
+
 ### Installation
 
 botogram is currently in development, so a release doesn't exist yet.  
 But if you want to install it anyway, you can clone the repository and install
-it with setuptools. Be sure to have Python 3, pip and setuptools installed:
+it with setuptools. Be sure to have Python 3.4 (or a newer version), pip,
+virtualenv and setuptools installed:
 
     $ git clone https://github.com/pietroalbini/botogram.git
     $ cd botogram

docs/install.rst

@@ -9,8 +9,8 @@ Installation of botogram
 
 botogram is available `on the Python Packages Index`_, so you can install it
 really easily with the `pip`_ command-line utility. Before installing it, be
-sure to have Python_ 3, pip_ and setuptools_ installed on your system. Then,
-issue the following command::
+sure to have Python_ 3.4 (or a newer version), pip_, virtualenv_ and setuptools_
+installed on your system. Then, issue the following command::
 
    $ pip3 install botogram