ui_interface: remove unused NotifyBlocksChanged signal
Create new signal for notification of new blocks.  Use w/ -blocknotify
cleanup include of assert.h
rpc: Compute number of confirmations of a block from block height

Currently this uses a CMerkleTx, but that makes no sense as we
have the CBlockIndex available. As noted by @jgarzik.
Move CMerkleTx to wallet.cpp/h

It is only used by the wallet so it has no place in main.
Merge pull request #4599
missing include boost/algorithm/string/replace.hpp
Merge pull request #4788
Merge pull request #4778
Replace weird characters by normal spaces
Merge pull request #4781

187115c cleanup include of assert.h (Philip Kaufmann)
Merge pull request #4789

bac5586 Replace weird characters by normal spaces (Pieter Wuille)
changed field types in some structures to equivalent unambiguous types

Conflicts:
	src/core.cpp

Rebased-By: Wladimir J. van der Laan
Github-Pull: #4180
Clean up CMerkleTx::SetMerkleBranch.

The case SetMerkleBranch(NULL) was never actually used, and thus the
involved code (loading the block from disk) can be removed and the
implementation simplified.