clarify docs about python support

doc/source/install.rst

@@ -6,7 +6,7 @@ using ``pip install larigira``. Or you can ``git clone
 https://git.lattuga.net/boyska/larigira.git`` and run ``python setup.py install``.
 As always, the usage of a virtualenv is recommended.
 
-The only supported python version is 3.4.
+Python greater or equal than 3.4 is supported.
 
 Configuration
 ---------------
@@ -22,7 +22,7 @@ inside ``~/.mpdconf``, add the following line::
     bind_to_address "~/.mpd/socket"
 
 For larigira, you need to set the ``MPD_HOST`` environment variable to
-``$HOME/.mpd/socket``. If you don't do this, you'll find many::
+``$HOME/.mpd/socket``. If you don't do this, you'll find many lines like these in the logs::
 
     15:37:10|ERROR[Player:93] Cannot insert song file:///tmp/larigira.1002/audiogen-randomdir-8eoklcee.mp3
     Traceback (most recent call last):
@@ -83,6 +83,7 @@ CONTINOUS_AUDIOSPEC
     This variable should be set to the JSON representation of an audiospec describing how to generate new
     audios. The default is ``{"kind": "mpd", "howmany": 1}``. You could, for example, change it to
     ``{ "kind": "randomdir", "paths": ["/var/music"], "howmany": 10}``
+    or to ``{"kind": "mpd", "howmany": 5, "prefix": "background"}``.
 EVENT_FILTERS
     See :doc:`eventfilters`
 LOG_CONFIG

setup.py

@@ -113,6 +113,11 @@ setup(
     },
     classifiers=[
         "License :: OSI Approved :: GNU Affero General Public License v3",
-        "Programming Language :: Python :: 3",
+        "Development Status :: 5 - Production/Stable",
+        "Programming Language :: Python :: 3.4",
+        "Programming Language :: Python :: 3.5",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Topic :: Multimedia :: Sound/Audio",
     ],
 )