implementation of periodic_update_index()
improved doc
Add modules management for apache
Fix argument name
Allows override of package name for require.nginx.server

This allow to install other packages like `nginx-extras` or
`nginx-light` instead of the default `nginx` package.
improved uptodate_index()
Merge branch 'main' into periodic_update_index

Conflicts:
	fabtools/system.py
opkg support
Fix cron.add_task to match changes to upload_template
Travis build environment no longer supports Python 2.5

http://about.travis-ci.org/blog/2013-11-18-upcoming-build-environment-updates/
Strip Travis CI badge from the PyPI description
Merge pull request #185 from lmeunier/nginx-custom-package-name

Allows override of package name for require.nginx.server
Merge pull request #181 from rybakit/apache

Add modules management for apache
clean up the commented-out lines
doc for opkg
Merge pull request #168 from ponty/periodic_update_index

implementation of periodic_update_index()
Allow pluralized time units in uptodate_index()
Fix test environment for Python 2.5

Python 2.5 did not ship with SSL, and recent version of pip default
to secure downloads, so we have to either find a way to install the
ssl module first, or just tell pip to use HTTP.
Add test for presence of systemd in service status checking
Backward compatibility for the apache module