Motivation / Problem

• TCPConnecter dtor was making illegal writes/reads when killed before resolving was done
• You couldn't query two servers at once

Both required fixing. And I had 2 code cleanups in my queue .. might as well add them.

Description

TCPConnecter dtor was a bit evil, as two problems intersected:

• connection_string was already free'd before the dtor of TCPConnecter was called. This was not expected. But because private/public wasn't set correctly for it, TCPQueryConnecter was already freeing the memory in his ctor. This was unintentional.
• TCPConnecter didn't join the resolve thread, so it could still be pending, and reading/writing information. Now instead, wait till the resolve thread finishes before destroying TCPConnecter.
• NetworkTCPQueryServer disconnected the network. No clue why .. most likely once that sounded like a good idea, but it is totally unneeded now.
• If you added a server that was already on the master-server listing, it was never marked as manual. So a game client restart still didn't make it show up. That is unexpected.
• While at it, also only query a server again if we didn't already have info about it. No need to constantly request information of a server .. it is unlikely to have changed.

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker