Add translation metadata support.

Allows user to control which posts are the translations independently of the
DEFAULT_LANG setting.
Merge pull request #830 from Rogdham/translation_metadata

Add translation metadata support.
Current default theme design is MIT licensed
Main CSS file uses tabs, not spaces
Change RELATIVE_URLS default to False - Fixes #829
Document supported Python versions
Remove allusion to Python versions less than 2.7
Fixed path_to_url when os.sep is not '/'.
Merge pull request #838 from jimperio/master

Make relative URLs work on Windows.
Merge pull request #837 from justinmayer/relativeoff

Change RELATIVE_URLS default to False - Fixes #829
.mailmap: Add mappings to consolidate author names and emails

See "MAPPING AUTHORS" in git-shortlog(1) for syntax details.

I don't think I've accidentally merged two distinct people together,
but I added

  Guillaume B <guitreize@gmail.com>

to avoid someone accidentally merging him into

  Guillaume <guillaume@lame.homelinux.com>

I'm pretty sure these are two different Guillaumes.
Merge pull request #839 from wking/mailmap

.mailmap: Add mappings to consolidate author names and emails
Better defaults for quickstart settings files

Since feed generation is usually unnecessary during development (and can
produce potentially-confusing warnings when SITEURL is not set), running
"make html" will now skip feed generation by default. Feed generation
settings have been added to publishconf.py so feeds will be generated
when the site is published.

Also corrected some URLs in pelicanconf.py.
remove plugins, update docs and update dependecies
Merge pull request #840 from avaris/move-plugins

remove plugins, update docs and adjust dependencies
Add contributors to THANKS. Minor language edits.
Warn user in case of missing title. Fixes #440.

When a WP XML file is imported, items with missing title are generated with a
title which is probably not the good one (instead of being dropped), and a
warning is displayed to the user.
remove unittest2 and fix various warnings in py3
remove warning for FEED_DOMAIN when SITEURL undefined
Merge pull request #841 from Rogdham/pelican-import_wp_no-title

Warn user in case of missing title. Fixes #440.