cc @jbenet

It's now possible to produce the DHT issues without process
orchestration.

Test1KBInstantaneous fails

@jbenet @whyrusleeping

pprof cannot be used reliably on OS X. This provides two make tasks to
collect and analyze profiling data.

To run profiling in a dockerized linux environment...
```
make // or `make collect`
```

To analyze results on host machine...
```
make analyze
```

@jbenet @whyrusleeping

@whyrusleeping @jbenet this is a WIP with the DHT.

wip

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

Conflicts:
	epictest/addcat_test.go
	exchange/bitswap/testnet/peernet.go
	exchange/bitswap/testutils.go
	routing/mock/centralized_server.go
	routing/mock/centralized_test.go
	routing/mock/interface.go

fix(routing/mock) fill in function definition

https://travis-ci.org/jbenet/go-ipfs/jobs/45000756

cc @whyrusleeping @jbenet

lol this is starting to happen pretty often

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

so it'll be easier to create another implementation using the new
mocknet

dht fixes

TestProversMany still fails

odd behavior: only one dht (the last one) is seeing
changes to its routing table.

i made a separate function because we may want to update our
routing table based on "closer peers". maybe not-- these could
all be lies.

Withe queries (particularly providers), it was possible to
exit the query runner's Run BEFORE all its children were done,
because the runner itself only listened to the context. This
introduced the possibility of a panic (you can go check it
out by running the TestProvidersMany test on dht_test in commits
before this one).  Thankfully, ctxgroup saved the day with
almost _zero_ changes to the sync flow, and now we have the
guarantee that the query runner will only exit if all its
children are done. ❤

Conflicts:
	routing/dht/query.go