Add rpc command 'getunconfirmedbalance' to obtain total unconfirmed balance

Conflicts:
	src/rpcserver.cpp
Remove -logtodebugger

`-logtodebugger` is a strange, obscure, WIN32-only (mostly MSVC) thing.
Let's clean up the options a bit get rid of it.

test_bitcoin was using fLogToDebugger as a way to prevent logging to
debug.log. For this, add a boolean (not exposed as option) fLogToDebugLog that
defaults to true and is disabled in the tests.
qt: Prevent non-functional GUI from popping up during Init

When a InitError or InitWarning happens, the
GUI pops up but is unusable (until Init finishes).

This is caused by showNormalIfMinimized. Add a message
flag to skip this call for Init errors or warnings.
qt: Make sure overviewpage button is pressed at startup

Due to walletframe changes, the overview page button is no longer
automatically selected at startup even though the overview page is shown.
Merge pull request #3438

d2b6de0 qt: Make sure overviewpage button is pressed at startup (Wladimir J. van der Laan)
qt: Treat regtest as testnet

No need to do anything special in the GUI for regtest mode,
but do treat it at testnet not mainnet to prevent confusion.
Merge pull request #3437

2ea980a qt: Treat regtest as testnet (Wladimir J. van der Laan)
Merge pull request #3369

6027b46 Add rpc command 'getunconfirmedbalance' to obtain total unconfirmed balance (Michael Bauer)
Merge pull request #3416

9e9056c Remove -logtodebugger (Wladimir J. van der Laan)
init: add better formating for some command-line options
[Qt] coin control change address handling update

- re-work change address handling so that default is CNoDestination(),
  until a verified and known change address was entered (easier code flow)
- add a missing NULL pointer check for adresstablemodel
- add a missing text when opening coin control address selection for
  priority and ensure the label is black
- add a missing . at the end of a sentence
Merge pull request #3439

3c95599 init: add better formating for some command-line options (Philip Kaufmann)
Merge pull request #3391

3380713 [Qt] coin control change address handling update (Philip Kaufmann)
qt: make wallet test consistent

Add a function `WaitBlocks` to wait for blocks to propagate to all three
nodes, and use this instead of waiting a fixed time of one second.

Fixes #3445.
extend std::exception logging in txdb.cpp
Merge pull request #3451

5fe19d6 qt: make wallet test consistent (Wladimir J. van der Laan)
Explicitly ensure that wallet is unlocked in `importprivkey`

This makes for a more useful error reply (fixes #957).
Merge pull request #3427

1ad2636 qt: Prevent non-functional GUI from popping up during Init (Wladimir J. van der Laan)
Merge pull request #3457

d78f35a Explicitly ensure that wallet is unlocked in `importprivkey` (Wladimir J. van der Laan)
Merge pull request #3453

96e5f61 extend std::exception logging in txdb.cpp (Philip Kaufmann)