API endpoint getfeeds: don't include the raw icons any more

for 80+ feeds, getfeeds alone resulted in 500KB-sized traffic every
five minutes, this is unacceptable for mobile!

upcoming: own API endpoint for icons, with caching
add rusha.js SHA1 module
console.js: also extend warn-method to use groups
add JS component feedicons

this component is responsible for persisting the feed icons on client side
clients without LSO don't get custom icons at all, just the default icon
view.menu: update icons upon event
add web-app stuff and a stupid basic icon
feed inject script: refresh height every 500ms from DOMContentLoaded until onReady

This helps to avoid double-scrollbaring due to pictures without explicit height=xxx declaration. These get loaded (and influence the document height) *after* DOMContentLoaded, so until they are fully loaded a double scrollbar will appear.

This issue is mostly existing on low-speed connections (tethered EDGE) or crappy WiFi.
Login/out: remember password

Browsers (I'm looking at you, Chrome) are too fucking stupid to remember
passwords in SPA sites (see http://stackoverflow.com/questions/19568719/html-single-page-application-fill-username-and-passwords-with-browser)...
so we have to roll our own storage. We use localStorage if available (cookies could be stolen/intercepted!).