AddToWallet implies BindWallet

Now that AddToWallet is called when loading transactions from the
wallet database, BindWallet can be integrated into that and does not
need to be an extra step.

Leaves behaviour unchanged, but makes the
fFromLoadWallet/!fFromLoadWallet paths in AddToWallet a bit more
symmetric.
Also switch the (unused) verification code to low-s instead of even-s.

a81cd968 introduced a malleability breaker for signatures
(using an even value for S). In e0e14e43 this was changed to
the lower of two potential values, rather than the even one.
Only the signing code was changed though, the (for now unused)
verification code wasn't adapted.
Fix script test handling of empty scripts

Previously an empty script would evaluate to OP_0
Test CHECKMULTISIG with m == 0 and n == 0
Fix bloom filter not to use bit_mask
Added instructions for when wrong openssl detected after brew link
Doxygen-compatible comments in coding style
Restart-warning for spendZeroConfChange option

According to the options model, a restart is required after changing this option. So let's notify the user about it.
Fix a typo in RPC signrawtransaction help
Merge pull request #4020

71f82bf Restart-warning for spendZeroConfChange option (langerhans)
doc: remove versions from build-unix.md, just refer to release-process.md

No one bothers to keep this up to date.
Better to refer to another file than give wrong information.
gitian: upgrade miniupnpc input to 1.9

Bumps deps-linux, deps-win dependency versions as well.

qt-win does not need to be bumped, as although it depends on deps-win,
Qt doesn't use miniupnp. I verified this by rebuilding the dependency
and checking the the output is the same. Not having to rebuild Qt is a
good thing as it is huge.
Bugfix: configure: Look in libx32 subdirectory for boost libraries
doc: update expected intermediate dependency hashes

Also move them to release-process.md from gitian-building.md for more
visibility.
Merge pull request #4031

f3f2cb7 doc: remove versions from build-unix.md, just refer to release-process.md (Wladimir J. van der Laan)
Changed bitrpc.py's raw_input to getpass for passwords to conceal characters during command line input. Getpass is in Python stdlib so no additional dependencies required.
Merge pull request #4024

ab64381 Fix a typo in RPC signrawtransaction help (Hector Jusforgues)
Prevent socket leak in ThreadSocketHandler.

When we are over our outbound limit ThreadSocketHandler would try to
 keep the connection if the peer was addnoded.

This didn't actually work for two reasons: It didn't actually run
 the accept code due to mistaken code flow, and because we have a
 limited number of outbound semaphores it couldn't actually use the
 connection.

Instead it leaked the socket, which might have caused issue #4034.

This patch just takes out the non-functioning white-listing for now.
Merge pull request #4033

219b512 doc: update expected intermediate dependency hashes (Wladimir J. van der Laan)
25d4911 gitian: upgrade miniupnpc input to 1.9 (Wladimir J. van der Laan)
Correct some proxy related socket leaks.