oembed 7.x-0.1-beta3

Changes since 7.x-0.1-beta2:

• Fixed MediaInternetOEmbedHandler did not implement validate() for invalid oEmbed files or when the server is unable to make requests.
• #1377690: Fixed the 'rich' oEmbed type should be mapped to a 'text/oembed' MIME type rather than 'html/oembed' to better fit the common IANA types.
• Cleaned up media_oembed_media_internet_providers().
• #1264942: Removed unnecessary functions media_oembed_install() and media_oembed_uninstall().
• #1403084 by Dave Reid: Trim $file->filename to 255 characters.
• #1403092 by Dave Reid: Move MediaInternetOEmbedHandler into its own file that can be autoloaded.
• generate alt attribute for images with same function.
• #1294824 by effulgentsia: Clear all oembed caches for a URL.
• #1289202 by effulgentsia: wmode for flash embed
• add soundcloud and twitter endpoints.
• convert simplexmlelement into std class for serialization.
• remove automatic paragraph elements around embed short codes.
• rename oembed module permission.
• remove presets.
• #1298566 by effulgentsia: Allow Media Browser Plus, or other modules, to autopopulate fields from oEmbed data
• #1305650 by effulgentsia: attempt to render thumbnails regardless of oembed type.
• #1305650 by effulgentsia: render generic icon when thumbnail is not available.
• change package of embed field module.
• #1298562 by ksenzee, effulgentsia: Re-use file assets and avoid PDO exception when adding a duplicate URL.
• #1255446 by bangpound: Reconstitute URL with optional components in link field formatter.
• update all schemes and endpoints of default providers.