depends: fix typo in source downloading. Regression from c897b1e732.

Some sources are renamed after download, since the filenames don't play nice
with (for example) gitian. This fixes the rename.

Needed for OSX build as it renames a file.
travis: add osx build
remove dup include of foreach.hpp in script.cpp
Merge pull request #4843

81061ff travis: add osx build (Cory Fields)
e4cf9f8 depends: fix typo in source downloading. Regression from c897b1e732. (Cory Fields)
[Qt] copyright, style and indentation cleanup of Qt tests
Merge pull request #4850

1ffb99b [Qt] copyright, style and indentation cleanup of Qt tests (Philip Kaufmann)
Improve readability of CAddrInfo::IsTerrible

- Replaced 86400 with 24*60*60
- Remove references to specific timespans in comments

Github-Pull: #4724
univalue: make spaceStr thread-safe

Simply add spaces to the existing string instead of using a
temporary.

Fixes #4756.
Fix make_change to not create half-satoshis
Merge pull request #4836 from morcos/fix-make_change

Fix make_change to not create half-satoshis
Merge pull request #4849

a264e44 remove dup include of foreach.hpp in script.cpp (Philip Kaufmann)
Cleanup messy error messages
Merge pull request #4839

346193b Cleanup messy error messages (R E Broadley)
Merge pull request #4851

41ef558 univalue: make spaceStr thread-safe (Wladimir J. van der Laan)
Headers-first synchronization

Many changes:
* Do not use 'getblocks', but 'getheaders', and use it to build a headers tree.
* Blocks are fetched in parallel from all available outbound peers, using a
  limited moving window. When one peer stalls the movement of the window, it is
  disconnected.
* No more orphan blocks. At all. We only ever request a block for which we have
  verified the headers, and store it to disk immediately. This means that a
  disk-fill attack would require PoW.
* Require protocol version 31800 for every peer (released in december 2010).
* No more syncnode (we sync from everyone we can, though limited to 1 during
  initial *headers* sync).
* Introduce some extra named constants, comments and asserts.

This breaks reindexing, which cannot yet deal with out-of-order blocks on disk.
RPC additions after headers-first
Remove CheckMinWork, as we always know all parent headers
Add CaughtUp() function (needed by later commits)
Improve getheaders logging
debug "block"