document how to change daemon ports

i took @jbenet's suggestion, but reorganised it a bit to *not* suggest what is actually warned against later. :)

explain what direct/indirect/recursive means

i couldn't understand what those meant. it was explain (at least partly) in #590 so let's share the goods!

this more clearly explains that the daemon is listening on the network. it also hints as to how to change the listening ports. this is also related to #874

query: fixed race condition

this time just move to goprocess

Correct link to paper

Ipns/refactor unixfs

take offset into account for computing read size

Fix nofuse build tags syntax

implement a worker to consolidate HasBlock provide calls into one 

simple nofuse build tag 

peer short tags are improved

t0110: cleanup using expr

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>

fix the tests

closes #836

this is ugly. ideally would seed using date, but unclear
what a portable datetime is. date '+%s' doesnt work on osx.

ideally this port would be a randomly picked unused port.
for now we just pick a different port than t0110-gateway.

we have a problem where initializing daemons with the same api port
often fails-- it hangs indefinitely. The proper solution is to make
ipfs pick an unused port for the api on startup, and then use that.
Unfortunately, ipfs doesnt yet know how to do this-- the api port
must be specified. Until ipfs learns how to do this, we must use
specific port numbers, which may still fail but less frequently
if we at least use different ones.

@whyrusleeping's fix in c88340b5 broke reading fuse in osx.
i'm not sure why... anyway, i chose to revert back to
io.ReadFull, but use the min of req.Size and r.Size(), which
should not encounter the reading problem in linux that a77ea2f0
fixed in the first place.

This commit also changes ipns, which had not been changed.