[Qt] Fix enable/disable show and remove buttons
Merge pull request #3927

ab1edd4 [Qt] Fix enable/disable show and remove buttons (Cozz Lovan)
Fix regression tests

Taught bitcoind to close the HTTP connection after it gets a 'stop' command,
to make it easier for the regression tests to cleanly stop.
Move bitcoinrpc files to correct location.
Tidied up the python-based regression tests.