Support for downloading extra artwork from Fanart.tv (resolves #1023).

New image types include:
* clearart
* discart
* extrathumbs
* extrafanart
* logo
* banner
* landscape (16:9 Thumb)

There are a couple things that should be noted:
1. Only English images will be downloaded.
2. The fanart image is now downloaded from Fanart.tv if it can find one, otherwise it uses TMDB
like it used to.  This is because the images on Fanart.tv tend to be higher resolutions &
quality.
3. Since multiple extrathumbs and extrafanarts are downloaded into a subdirectory, subdirectories
are now supported for metadata file names.  The subdirectories will be automatically created if
they don't exist.
4. Bluray discart will always be preferred over DVD.  Ideally, it would prefer DVD versions for
SD quality movies, but I couldn't find an easy way to determine the quality from within the
plugin.  I suspect major changes would be needed to the plugin system in general in order to get
this to work.  If a user cares about the distinction, the best work-around is to not download
these in Couchpotato and run the Artwork Downloader addon from within XBMC.
5. A maximum of 4 extrathumbs and 20 extrafanarts will be downloaded.

Squashed commit of the following:

commit b113a4def197a9ca8545bde9f5081c0591b93b36
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Thu Apr 24 14:24:12 2014 -0500

    Bug-fix and code cleanup.

    Fixed a bug where the movie.info event would crash if there aren't any pictures to scrape in
    fanart.tv.

commit adf7a4675d472e9e95a316c6cccc681a52804f13
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 16:15:03 2014 -0500

    Added support for extrafanart.
    Also, the main fanart will be taken from fanart.tv unless one
    does not exist.

commit 1791e46c8602f40bb56fe0cf7ecb0607f35b4b12
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 15:13:14 2014 -0500

    Couchpotato now downloads extrathumbs from the extra tmdb backdrops if they exist.

    This commit made some major changes to the core image creation functionality that
    makes writing multiple images to folders possible.

commit c0858807873749dbc928c0260037138f51f894ca
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 12:18:53 2014 -0500

    Bug Fix & Implemented functionality to select bluray or dvd disc images.

    Currently, only blurays will be selected, unless there are no blurays.
    However, if a mechanism for determining the quality of the release is
    implemented, it would be simple to make this selection based on the
    quality.

commit 786751371d243f53d0f5c6f2c38d92288d8608ba
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 10:59:25 2014 -0500

    Fixed a bug where non-HD clearart and logos couldn't be downloaded.

commit feda8df483d13b5a5df3a869f25de8f2c7e6ffe3
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 10:12:31 2014 -0500

    Fixed some problems that were missed with the previous merge.

commit 5ddab6c40e69a5accc6c0336cd7485920ff82d8f
Merge: 7273abf ff46aa0
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 10:02:11 2014 -0500

    Merge branch 'develop' into fanarttv

    Conflicts:
    	couchpotato/core/media/movie/providers/info/themoviedb.py
    	couchpotato/core/providers/metadata/xbmc/__init__.py

commit 7273abf827735cf245711c3d3199a6a173a964aa
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Thu Feb 27 13:29:57 2014 -0600

    Downloads extra artwork from fanart.tv

    Downloads occur with correct filenaming when XBMC metadata is generated,
    but the image URLs are selected when the movie.info event is called.

commit 9080d9d749c7e1ddbdc78f7b37a3c5f83195d580
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Wed Feb 26 16:31:37 2014 -0600

    Added basic functionality for fanarttv provider.

    This should be mostly done and is based on the tvdb provider.

commit 1b39b246c2a9d65f9ef86c4e150a12d893e362c0
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Wed Feb 26 14:50:17 2014 -0600

    Updated fanarttv library with the correct package hierarchy
    (libs.fanarttv).

commit 8abb7c8f8ad3347900debb9f6a6d5a7acb7df396
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Wed Feb 26 13:12:48 2014 -0600

    Added fanart.tv API python library (lib.fanarttv).

    The upstream for this library is at
    https://github.com/z4r/python-fanart.
Added option to run the Artwork Downloader addon during XBMC notify.

This option will only work in XBMCv12 (Frodo) or later.  It also requires the Artwork Downloader
Addon.

Since XBMC's API doesn't support notifications over HTML, there is no way for couchpotato to know
when the Library Scan is complete.  Since running the Artwork Downloader before the movie has
been scanned won't solve anything, a delay timer can be adjusted to suit the user's needs.

Squashed commit of the following:

commit bd60ed585f77cc40c31fd67d4ae732e0845d31ab
Merge: fcb092e b113a4d
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Thu Apr 24 14:26:24 2014 -0500

    Merge branch 'fanarttv' into artdlnotify

commit b113a4def197a9ca8545bde9f5081c0591b93b36
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Thu Apr 24 14:24:12 2014 -0500

    Bug-fix and code cleanup.

    Fixed a bug where the movie.info event would crash if there aren't any pictures to scrape in
    fanart.tv.

commit fcb092e776e00ceabea016b3c26d9394e32d72b0
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Thu Apr 24 14:21:27 2014 -0500

    Option to run the artwork downloader addon during XBMC notify.

commit adf7a4675d472e9e95a316c6cccc681a52804f13
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 16:15:03 2014 -0500

    Added support for extrafanart.
    Also, the main fanart will be taken from fanart.tv unless one
    does not exist.

commit 1791e46c8602f40bb56fe0cf7ecb0607f35b4b12
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 15:13:14 2014 -0500

    Couchpotato now downloads extrathumbs from the extra tmdb backdrops if they exist.

    This commit made some major changes to the core image creation functionality that
    makes writing multiple images to folders possible.

commit c0858807873749dbc928c0260037138f51f894ca
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 12:18:53 2014 -0500

    Bug Fix & Implemented functionality to select bluray or dvd disc images.

    Currently, only blurays will be selected, unless there are no blurays.
    However, if a mechanism for determining the quality of the release is
    implemented, it would be simple to make this selection based on the
    quality.

commit 786751371d243f53d0f5c6f2c38d92288d8608ba
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 10:59:25 2014 -0500

    Fixed a bug where non-HD clearart and logos couldn't be downloaded.

commit feda8df483d13b5a5df3a869f25de8f2c7e6ffe3
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 10:12:31 2014 -0500

    Fixed some problems that were missed with the previous merge.

commit 5ddab6c40e69a5accc6c0336cd7485920ff82d8f
Merge: 7273abf ff46aa0
Author: Dan Boehm <dboehm.dev@gmail.com>
Date:   Wed Apr 23 10:02:11 2014 -0500

    Merge branch 'develop' into fanarttv

    Conflicts:
    	couchpotato/core/media/movie/providers/info/themoviedb.py
    	couchpotato/core/providers/metadata/xbmc/__init__.py

commit 7273abf827735cf245711c3d3199a6a173a964aa
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Thu Feb 27 13:29:57 2014 -0600

    Downloads extra artwork from fanart.tv

    Downloads occur with correct filenaming when XBMC metadata is generated,
    but the image URLs are selected when the movie.info event is called.

commit 9080d9d749c7e1ddbdc78f7b37a3c5f83195d580
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Wed Feb 26 16:31:37 2014 -0600

    Added basic functionality for fanarttv provider.

    This should be mostly done and is based on the tvdb provider.

commit 1b39b246c2a9d65f9ef86c4e150a12d893e362c0
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Wed Feb 26 14:50:17 2014 -0600

    Updated fanarttv library with the correct package hierarchy
    (libs.fanarttv).

commit 8abb7c8f8ad3347900debb9f6a6d5a7acb7df396
Author: dan <dan@DBoehm-Arch.danboehm>
Date:   Wed Feb 26 13:12:48 2014 -0600

    Added fanart.tv API python library (lib.fanarttv).

    The upstream for this library is at
    https://github.com/z4r/python-fanart.