Chain reorgs weren't properly handled when a chain was further ahead.
Previously we'd end up with mixed chains in our canonical numbering
sequence. Added test for this type of forking.

```
     /-o-o-o   A
o-C-+
     \-o-o-o-o B
```

Ends up with with C A1, A2, A3, B4

Insert blocks will no longer allow processing of multiple chains at the
same time. The block lock has been moved to start of the function.

Remove path separator literals

p2p/discover: fix api issues caused by leveldb update

rlp: fix list bounds check overflow (found by go-fuzz)

p2p/discover: persistent node database

godeps: refresh leveldb, clean up stale dependencies

Conflicts:
	rpc/api.go

Whisper cleanup, part 3

The list size checking overflowed if the size information
for a value was bigger than the list. This is resolved by
always performing the check before reading.

Ref: https://github.com/Gustav-Simonsson/go-ethereum/commit/21c4c155ee68890a069654dcc5bc083a867f65cd

Remove old logger from RPC pkg

Add privkey loading to block tests