Change one of the "ipfs" to "ipns"

Fix: dnslink domain resolving was broken; Add: no caching for those

t0040: test ipfs add with stdin

Let's test 'ipfs add' with stdin input too.

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

fix minor data race in bitswap

make bitswap commands error out properly offline

Bug/panic on empty path

Update the previous `invalid path` error to match the error returned
from `SplitAbsPath`.

Cleaned the tests, and actually test for the error.

Added the original logic to check for a invalid path and a simple test.

If no path after `/ipfs/` or `/ipns/` is given, then the daemon will
panic with a slice bounds out of range error. This checks to see if we
have anything after `ipfs` or `ipns`.

trying to debug permissions failure

fix offline full path resolution bug

large refactor of bitswap, implement wantmanager to manage wantlist

Also more refactoring of bitswap in general, including some perf
improvements and eventlog removal.

clean up, and buffer channels

move some things around

correctly buffer work messages

more cleanup, and improve test perf

remove unneccessary test

revert changes to bitswap message, they werent necessary

silence error log on shutdown

fixes #1234
fixes #1267