Reject non-canonically-encoded sizes

The length of vectors, maps, sets, etc are serialized using
Write/ReadCompactSize -- which, unfortunately, do not use a
unique encoding.

So deserializing and then re-serializing a transaction (for example)
can give you different bits than you started with. That doesn't
cause any problems that we are aware of, but it is exactly the type
of subtle mismatch that can lead to exploits.

With this pull, reading a non-canonical CompactSize throws an
exception, which means nodes will ignore 'tx' or 'block' or
other messages that are not properly encoded.

Please check my logic... but this change is safe with respect to
causing a network split. Old clients that receive
non-canonically-encoded transactions or blocks deserialize
them into CTransaction/CBlock structures in memory, and then
re-serialize them before relaying them to peers.

And please check my logic with respect to causing a blockchain
split: there are no CompactSize fields in the block header, so
the block hash is always canonical. The merkle root in the block
header is computed on a vector<CTransaction>, so
any non-canonical encoding of the transactions in 'tx' or 'block'
messages is erased as they are read into memory by old clients,
and does not affect the block hash. And, as noted above, old
clients re-serialize (with canonical encoding) 'tx' and 'block'
messages before relaying to peers.
Squashed 'src/leveldb/' changes from be1b0ff..936b461

936b461 Merge upstream LevelDB 1.13.
748539c LevelDB 1.13

git-subtree-dir: src/leveldb
git-subtree-split: 936b4613ea4551992e6096b1e05eeefc09a20e3b
Merge src/leveldb changes for LevelDB 1.13
[wallet] Consider generated coins mature at COINBASE_MATURITY+1

We're not seeing large reorgs that would justify waiting a large
 amount past the rule required maturity, and the extra three
 hours is just a nuisance. Take one more block to at least give
 the 100th block time to propagate.
improve wallet load time by removing duplicated calls to EC_KEY_check_key and adding a hash for vchPubKey/vchPrivKey entries in wallet.dat

backwards compatible with previous wallet.dat format
verify vchPubKey matches calculated public key unless fSkipCheck is set
Rename -tor to -onion to better reflect what it does.

I've seen users confused multiple times thinking they
 should be using -tor to set their tor proxy and then
 finding in horror that they were still connecting to
 the IPv4 internet.

Even Jeff guesses wrong about what the knob does, so
 I think we should rename it. This leaves the old
 knob working, we can pull it out completely in a
 later release.
Add getnetworkhashps to get the calculated network hashrate
[Fee logic] Don't count txins for priority to encourage sweeping.

This changes the priority calculation to not include the size of per-txin
 data including up to 110 bytes of scriptsig so that transactions which
 sweep up extra UTXO don't lose priority relative to ones that don't.

I'd toyed with some other variations, but it seems like any formulation
 which results in an incentive stronger than making them not count will
 sometimes create incentives to add extra outputs so that you have
 extra inputs to consume later.  The maximum credit is limited so that
 users don't lose the disincentive to stuff random data in their
 transactions, the limit of 110 is based on the size of a P2SH
 redemption with a compressed public key.

This shouldn't need a staged deployment because the priority is not
 used as a relay criteria, only a mining criteria.
Update contrib/debian: proper desktop category and update changelog
Inline signature serializer

Instead of building a full copy of a CTransaction being signed, and
then modifying bits and pieces until its fits the form necessary
for computing the signature hash, use a wrapper serializer that
only serializes the necessary bits on-the-fly.

This makes it easier to see which data is actually being hash,
reduces load on the heap, and also marginally improves performances
(around 3-4us/sigcheck here). The performance improvements are much
larger for large transactions, though.

The old implementation of SignatureHash is moved to a unit tests,
to test whether the old and new algorithm result in the same value
for randomly-constructed transactions.
misc small spelling/indentation fixes
Hardcode string in miniupnpcstring.h and remove wine requirement from deps-win32.yml

Credit: sipa, cfields, Luke-Jr and michagogo contributed to this fix.

Removing wine as a win32 build dep is beneficial to fixing Gitian LXC,
which would enable many more people to join in the gitian.sigs process
by being able to build with a linux VM instead of a virt capable host.
Merge pull request #3045 from Diapolo/master

misc small spelling/indentation fixes
Bitcoin-Qt: add missing change from branch Qt_misc

- remove an unneeded debug message in walletframe
Merge pull request #3042 from wtogami/nowinedep

Hardcode string in miniupnpcstring.h and remove wine from deps-win32.yml
Bitcoin-Qt: translation fixes in sendcoins

- remove some unneeded translatable strings from sendcoinsentry.ui file and
  rename some elements for better readability
- optimize string prorcessing in SendCoinsDialog::on_sendButton_clicked()
- make all UI labels for secure payments plain text and move the settings
  to sendcoinsentry.ui file
- remove unneeded button and default button definiton from warning message
  boxes
- remove fixed font-size when sending coins to an address with label and
  use monospace font for addresses
Merge pull request #2888 from litecoin-project/getnetworkhashps

Add getnetworkhashps to get the estimated network hashrate
Merge pull request #2991 from Diapolo/translation_fixes

Bitcoin-Qt: translation fixes in sendcoins
Support absence of wallet (pwalletMain==NULL) in several locations,
notably RPC.