qt: Add closing newline to help message

`bitcoin-qt --help` was missing a final newline.
Re-add BTC/KB in help message for `settxfee`

Commit a22eed6a got reverted in a RPC documentation update, redo it.
Use standard BIP 22 rejection reasons where applicable
Support for error messages and a few more rejection reasons
Merge pull request #3370 from sipa/headersfirst3

Prepare block connection logic for headers-first
Merge pull request #3588

df966d1 log parameter interactions to debug.log (Philip Kaufmann)
Add more data-driven tests.
Final bitcoin_en update before 0.9.0rc1

Just for completeness. Only a few messages changed or moved since last time.

Don't change any translatable messages until 0.9 final unless really necessary.
Merge pull request #3601

c32a486 Add more data-driven tests. (Matt Corallo)
Fix build time when building from tarball (now really)

Don't define BUILD_DATE at all when no git version information
is available. `version.cpp` will then define it for us correctly
to the last commit date.

This has been fixed and broken many times over 0.9 history
(21cc8bd, ef1e984), please don't touch this code unless you plan
on testing all possible scenarios including gitian builds.

Fixes #3570.
doc: Add historical release notes

Add all known release notes for versions since 0.3.12,
thanks to Matt Corallo for collecting them on the wiki.
small changes to rpc command help message strings
Merge pull request #3592

c117d9e Support for error messages and a few more rejection reasons (Luke Dashjr)
14e7ffc Use standard BIP 22 rejection reasons where applicable (Luke Dashjr)
Merge pull request #3605

69baec9 doc: Add historical release notes (Wladimir J. van der Laan)
build: Make sure historical release notes end up in distributions

Adds the historical release notes to release tarballs and windows
installers.
Limit the number of orphan blocks

In case the total number of orphan blocks in memory exceeds a limit
(currently set to 750), a random orphan block (which is not
depended on by another orphan block) is dropped. This means it will
need to be downloaded again, but it won't consume memory until then.
[Qt] Fix nTransactionFee in qt-settings
[Qt] Improve single step in bitcoinamountfield
Gitian fixes for 0.9.0rc1 build

- Add 'g++' package (virtualbox images don't have this by default)
- Workaround for determinism in Qt5 resources
- Pass --disable-maintainer-mode --disable-dependency-tracking to
  configure for libqrencode to avoid random errors about missing m4
  directory
- Fix typo -with-pic -> --with-pic

It is not necessary to rebuild dependencies after this commit.
Fixes #3610 and #3612.
added missing homebrew qt dependency on mac osx build documentation.