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
sendcoinsentry: small clear() and setValue() changes

- clear(): clear all UI elements (for secure and insecure payments)
- setValue(): only modify UI elements, which need to be set (for secure
  or insecure payments)
sendcoinsdialog: display real failed address string

- display the real string (faulty address), which causes the valid address
  check to fail, instead of a stringified "nonsense" CBitcoinAddress
paymentserver: use own HTML-esc / add new header const

- make processPaymentRequest() use our own HTML-escaping function from
  GUIUtil
- make string "application/bitcoin-payment" a constant (below similar
  constant strings in the .cpp file)
Refactor/encapsulate chain globals into a CChain class
Add network traffic graph
[doc] Add testnet hidden service port to the example tor config.

Seems like there are a lot of advertised testnet HS nodes that
don't actually work. Lack of the testnet port on the example
HS config might be one reason.
Merge pull request #3089 from gmaxwell/hsport

[doc] Add testnet hidden service port to the example tor config.
Merge pull request #2933 from sipa/leveldb113

Merge upstream LevelDB 1.13
Merge pull request #3077 from sipa/chain

Refactor/encapsulate chain globals into a CChain class
Avoid core dump if rpc port is in use.

The cleanup code needs to check for NULL rpcworkers thread group.
misc spelling / space / style fixes
Merge pull request #3091 from Diapolo/misc

misc spelling / space / style fixes
Merge pull request #2924 from sje397/TrafficGraph

[QT] Add network traffic graph to debug window
replace %zu with %"PRIszu" macro to prevent compiler warnings
Merge pull request #3093 from Diapolo/printf_format

replace %zu with %"PRIszu" macro to prevent compiler warnings
Merge pull request #3080 from Diapolo/sendcoins-paymentreq

Bitcoin-Qt: misc changes for sendcoins and paymentsever