This commit adds a basic infrastructure to allow upgrades to happen to
btcd as needed. This paves the way for the upcoming data path changes to
be automatically updated for the user as needed and also ensures any
future changes that might require upgrades already have an established
way of performing the needed upgrades.
Although not required if the proxy set is indeed Tor, setting this option
does the following:
- Sends DNS queries over the Tor network (during dns seed lookup). This
stops your IP from being leaked via DNS.
- Does not disable the listening port. This allows the hidden services
feature of Tor to be used.
