Drop feeds 0.9.3c

• Improve UIs loading time
• Improve statusbar messages
• When filter is active displays all feeds
• Custom date time format for the render feed tab
• Add methods getFeedInfo() and rssFromFeedInfo() to USTools lib for user scripts (documentation will come later, in the meantime you can take a look to the youtube userscript exemple)
• Fix script editor ctrl hot keys management (ctrl+s, ctrl+z, ctrl+y)
• Fix feed sort when many Firefox windows are opened
• Fix Run an automatic feed update on start
• Fix youtube feed detection
  a:
• Update USTools help
• Fix autoupdate on start with many opened windows
• Fix subscribe feed list when titles are empty (use a default title)
• Fix discovering feeds view
  b:
• Fix attribute extraction in ATOM Feeds
  c:
• Fix "open unread feeds in new tabs" button