ui_interface: remove unused NotifyBlocksChanged signal
Create new signal for notification of new blocks.  Use w/ -blocknotify
depends: add a fallback path in case package sources go missing

If a source url fails to download, try again at
$FALLBACK_DOWNLOAD_PATH/file.name, where FALLBACK_DOWNLOAD_PATH can be
overridden by the user.
Move UpdateTime to pow
Move CBlockIndex::GetBlockWork() to pow::GetProofIncrement(nBits)
replace ComputeMinWork with CheckMinWork
Bypass reloading blocks from disk
Perform CVerifyDB on pcoinsdbview instead of pcoinsTip

Bypassing the main coins cache allows more thorough checking with the same
memory budget.

This has no effect on performance because everything ends up in the child
cache created by VerifyDB itself.

It has bugged me ever since #4675, which effectively reduced the
number of checked blocks to reduce peak memory usage.

- Pass the coinsview to use as argument to VerifyDB

- This also avoids that the first `pcoinsTip->Flush()` after VerifyDB
  writes a large slew of unchanged coin records back to the database.
depends: add sensible download timeout/retry values
Merge pull request #4752

df7565d depends: add sensible download timeout/retry values (Cory Fields)
c897b1e depends: add a fallback path in case package sources go missing (Cory Fields)
Revert "Add a getutxos command to the p2p protocol. It allows querying of the UTXO set"

This reverts commit da2ec100f3681176f60dec6dc675fc64147ade3a.
Merge pull request #4764

92bb6f2 Bypass reloading blocks from disk (Pieter Wuille)
Merge pull request #4377

654871d replace ComputeMinWork with CheckMinWork (jtimon)
b343c1a Move CBlockIndex::GetBlockWork() to pow::GetProofIncrement(nBits) (jtimon)
c2c02f3 Move UpdateTime to pow (jtimon)
Fix build with DEBUG_LOCKORDER

Fixes #4771
fix comments ExtractAddress() -> ExtractDestination()
qt/splashscreen: #include version.h

Needed to build breakage reported by Arnavion on IRC:
qt/splashscreen.cpp: In constructor 'SplashScreen::SplashScreen(const QPixmap&, Qt::WindowFlags, bool)':
qt/splashscreen.cpp:33:98: error: 'FormatFullVersion' was not declared in this scope
Add travis build:passing/failing indicator.
Fix a few "Uninitialized scalar field" warnings

Fix a few warnings reported by Coverity.
None of these is critical, but making sure that class fields are
initialized can avoid heisenbugs.
Merge pull request #4766

5a0823a Add travis build:passing/failing indicator. (randy-waterhouse)
Merge pull request #4772

87d9819 fix comments ExtractAddress() -> ExtractDestination() (jtimon)