README: update links.

The documentation link was pointing at the pre 0.9 version.
The edoc docs are not working right, so I dropped the link to those until the edoc's are back.
core: Start folsom in boot sequence

Otherwise Zotonic crashes on startup with:

21:01:38.682 [error] CRASH REPORT Process <0.173.0> with 0 neighbours exited with reason: bad argument in call to ets:member(folsom, {zotonic,webzmachine,requests}) in folsom_ets:handler_exists/1 in gen_server:init_it/6
mod_base: Match the websocket protocol on the WS handshake.

This fixes websockets on mobile safari 5 for SSL websocket
connections.
Update nl.po

Typo
Merge pull request #682 from ArthurClemens/patch-8

Update nl.po
core: add z_datetime:timestamp/0. Also use a constant for fixed 1970 base seconds.
mod_base: use window.location.host for websocket stream, unless configured otherwise.
Also add try/catch around websocket connect, to catch potential IE10 security exception.
core: new state machine for maintaining websocket/comet push connections.
Perpetual comet loop which only polls if there is no active websocket connection.
Websocket connection checks with a periodic ping/pong if the connection works.
mod_base: fix for subdomain polling loop.

(cherry picked from commit bcd55efe10486454ce433feb91dfa467edb41bc7)
Fix wrong filter in example
doc: add missing `use_absolute_url` arg in example.
Merge pull request #684 from ArthurClemens/patch-9

Fix wrong filter in example