Removed LevelDB changes

Syntax Highlighting
better std::exception logging for CAddrDb

- also small logging text changes
stop bitcoind/bitcoin-cli processes that might have been left running
Branding
don't use sed's -i option to stay posix compliant

POSIX does not define sed's -i option. To stay as portable
as possible we should not relay on it.
doc: remove specific mention of boost 1.55

There is no need to use any specific version of boost on Linux/Unix.
Even 1.37 should still work.

Also the mention of boost-dev doesn't belong after adding oldstable.
Remove it. libboost-all-dev is already mentioned earlier.
Create (MANDATORY|STANDARD)_SCRIPT_VERIFY_FLAGS constants
Let tx (in)valid tests use any SCRIPT_VERIFY flag

Previously only P2SH could be set.
add DEFAULT_TRANSACTION_FEE constant in wallet

- as this is a shared Core/GUI setting, this makes it easier to keep them
  in sync (also no new includes are needed)

Conflicts:
	src/wallet.cpp
	src/wallet.h
rpc: add `getblockchaininfo` and `getnetworkinfo`

Adds two new info query commands that take over information from
hodge-podge `getinfo`.

Also some new information is added:
- `getblockchaininfo`
  - `chain`: (string) current chain (main, testnet3, regtest)
  - `verificationprogress: (numeric) estimated verification progress
  - `chainwork`
- `getnetworkinfo`
  - `localaddresses`: (array) local addresses, from mapLocalHost (fixes #1734)

Conflicts:
	src/rpcblockchain.cpp
	src/rpcnet.cpp
Remove NumBlocksOfPeers

Generally useless information. Only updates on connect time, not after
that. Peers can easily lie and the median filter is not effective in
preventing that.

In the past it was used for progress display in the GUI but
`CheckPoints::guessVerificationProgress` provides a better way that is now used.
It was too easy to mislead it. Peers do lie about it in practice, see issue #4065.

From the RPC, `getpeerinfo` gives the peer raw values, which are more
useful.

Conflicts:
	src/main.cpp
[Qt] fix Qt slot problem in receivecoinsdialog

- fixes error from debug.log:
  QMetaObject::connectSlotsByName: No matching signal for
  on_recentRequestsView_selectionChanged(QItemSelection,QItemSelection)
- small style fixes (e.g. alphabetical ordering if includes etc.)
- fixes #3992