update bash-completion for v0.9

Recognize completable arguments of new and expanded commands.
Now that bitcoin-cli(1) exists, add completion for it as well.
Total money limit test

Added bounds check by @il--ya.

Updated-by: Wladimir van der Laan <laanwj@gmail.com>
Log which wallet is used during init

Now that the wallet can be selected using -wallet it is important
to log which wallet is being used for later troubleshooting.
Merge pull request #3805

8a6894c Log which wallet is used during init (Wladimir J. van der Laan)
Merge pull request #3768

fecba4e Total money limit test (Pieter Wuille)
Merge pull request #3796

16bfd68 update bash-completion for v0.9 (Christian von Roques)
Refactor proof of work related functions out of main