Win32: use a more modern API call in FileCommit()

- this seems to be a more recent API call and also supports e.g. SMB3,
  ReFS, which is not guaranteed for commit_()
- link to MSDN: http://msdn.microsoft.com/en-us/library/windows/desktop/aa364439%28v=vs.85%29.aspx
Fix off-by-one errors in use of IsFinalTx()

Previously CreateNewBlock() didn't take into account the fact that
IsFinalTx() without any arguments tests if the transaction is considered
final in the *current* block, when both those functions really needed to
know if the transaction would be final in the *next* block.

Additionally the UI had a similar misunderstanding.

Also adds some basic tests to check that CreateNewBlock() is in fact
mining nLockTime-using transactions correctly.

Thanks to Wladimir J. van der Laan for rebase.
[Qt] harmonize strings used when exporting in addressbookpage
Merge pull request #3579

f3005c8 [Qt] harmonize strings used when exporting in addressbookpage (Philip Kaufmann)
qt: Translation update

Update English .ts file from source as well as pull changes from transifex
to current translation.
Merge pull request #2342

665bdd3 Fix off-by-one errors in use of IsFinalTx() (Peter Todd)
[Qt] Fix coin control labels update
build: use -mwindows for gui targets when linking with mingw
use english for all reason strings in IsStandardTx()
Merge pull request #3589 from Diapolo/english-reason

use english for all reason strings in IsStandardTx()
Merge pull request #3591

6986861 build: use -mwindows for gui targets when linking with mingw (Cory Fields)
Add check for valid keys in `importprivkey`

The base58 armoring was checked, but not the resulting private key,
which could be out of range. Fix this by adding a check.
[Qt] fix bitcoin: URI strings (spelling fixes)
Merge pull request #3594

d7aa1ec [Qt] fix bitcoin: URI strings (spelling fixes) (Philip Kaufmann)
Merge pull request #3590

edd735d [Qt] Fix coin control labels update (Cozz Lovan)
Merge pull request #3593

c7f9332 Add check for valid keys in `importprivkey` (Wladimir J. van der Laan)
Merge pull request #3582

e5aadb2 Updated fallback seed nodes from sipa's DNS seeds (Gavin Andresen)
Re-add newline to error() messages

As reported by @Subo1978, error messages don't have a trailing newline
anymore after commit b77dfdc9. Add back this newline.
Merge pull request #3450

4c0b2cd Win32: use a more modern API call in FileCommit() (Philip Kaufmann)
Do not DoS-ban nodes that give us invalid blocks with valid proof-of-work

This relaxes the DoS rules (so cannot cause a network split), so nodes that
relay blocks with valid proof-of-work but contain an invalid transaction
are not banned.

See issue #3195 for the rationale.