p2p: introduce peerConn to simplify peer creation (#1226)

* expose AuthEnc in the P2P config

if AuthEnc is true, dialed peers must have a node ID in the address and
it must match the persistent pubkey from the secret handshake.

Refs #1157

* fixes after my own review

* fix docs

* fix build failure

```
p2p/pex/pex_reactor_test.go:288:88: cannot use seed.NodeInfo().NetAddress() (type *p2p.NetAddress) as type string in array or slice literal
```

* p2p: introduce peerConn to simplify peer creation

* Introduce `peerConn` containing the known fields of `peer`
* `peer` only created in `sw.addPeer` once handshake is complete and NodeInfo is checked
* Eliminates some mutable variables and makes the code flow better
* Simplifies the `newXxxPeer` funcs
* Use ID instead of PubKey where possible.
        * SetPubKeyFilter -> SetIDFilter
        * nodeInfo.Validate takes ID
        * remove peer.PubKey()

* persistent node ids

* fixes from review

* test: use ip_plus_id.sh more

* fix invalid memory panic during fast_sync test

```
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: panic: runtime error: invalid memory address or nil pointer dereference
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x98dd3e]
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]:
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: goroutine 3432 [running]:
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.newOutboundPeerConn(0xc423fd1380, 0xc420933e00, 0x1, 0x1239a60, 0
xc420128c40, 0x2, 0x42caf6, 0xc42001f300, 0xc422831d98, 0xc4227951c0, ...)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/peer.go:123 +0x31e
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.(*Switch).addOutboundPeerWithConfig(0xc4200ad040, 0xc423fd1380, 0
xc420933e00, 0xc423f48801, 0x28, 0x2)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:455 +0x12b
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.(*Switch).DialPeerWithAddress(0xc4200ad040, 0xc423fd1380, 0x1, 0x
0, 0x0)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:371 +0xdc
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: github.com/tendermint/tendermint/p2p.(*Switch).reconnectToPeer(0xc4200ad040, 0x123e000, 0xc42007bb00)
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:290 +0x25f
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: created by github.com/tendermint/tendermint/p2p.(*Switch).StopPeerForError
2018-02-21T06:30:05Z box887.localdomain docker/local_testnet_4[14907]: #011/go/src/github.com/tendermint/tendermint/p2p/switch.go:256 +0x1b7
```

test/p2p/data/core/init.sh

@@ -1,20 +0,0 @@
-#! /bin/bash
-# This is a sample bash script for tendermint core
-# Edit this script before "mintnet start" to change
-# the core blockchain engine.
-
-TMREPO="github.com/tendermint/tendermint"
-BRANCH="master"
-
-go get -d $TMREPO/cmd/tendermint
-### DEPENDENCIES (example)
-# cd $GOPATH/src/github.com/tendermint/abci
-# git fetch origin $BRANCH
-# git checkout $BRANCH
-### DEPENDENCIES END
-cd $GOPATH/src/$TMREPO
-git fetch origin $BRANCH
-git checkout $BRANCH
-make install
-
-tendermint node --p2p.seeds="$TMSEEDS" --moniker="$TMNAME" --proxy_app="$PROXYAPP" --rpc.unsafe

test/p2p/data/mach1/core/config/node_key.json

@@ -0,0 +1 @@
+{"priv_key":{"type":"ed25519","data":"06962D169F314ABB9D05AE5A04B46E48F0FBD8F1830149B47493910CBDCA7796096E5B94CD179F545AE3C281D9BF5C9E0E3D8FF719048B62F7849094CFFA8591"}}

test/p2p/data/mach2/core/config/node_key.json

@@ -0,0 +1 @@
+{"priv_key":{"type":"ed25519","data":"B8CE8B0D5138C10208526ABDADCE91C735FCCC4186E06E0972EC35E64973428A45EBC61F24CE1B91B3D26AFBAB11C2789EF04CBAC28183619C01116B66A9C528"}}

test/p2p/data/mach3/core/config/node_key.json

@@ -0,0 +1 @@
+{"priv_key":{"type":"ed25519","data":"913DE8AC6D18922A53F6B0196EF023B4693FECFBB565E084F0B4941768F3DAE892B35ADD954562FE071C465BC244B2AFAED4A270EC849269341473CE192DE682"}}

test/p2p/data/mach4/core/config/node_key.json

@@ -0,0 +1 @@
+{"priv_key":{"type":"ed25519","data":"408226F3F40411AC22262DD9A33BFE27D6FED42B9F084906B3797118C951CB82F81552170A85C94F0608AE8B59B70A0CA8B604A9057585B28A266140DC615E97"}}