This branch makes the following changes to the Tor plugin:
- Always start from the default settings, rather than reusing the torrc from the previous session
- Apply the ClientTransportPlugin settings once via torrc, rather than repeatedly applying them via the control port
- Keep track of the network settings that have been applied, and don't apply them to the control port unless the settings have changed
- Make fewer redundant calls to PluginCallback#pluginStateChanged()
These changes may help with #1499, specifically the cases where the crash happens at startup when bridges are enabled. My theory is that the crash may be caused by rapidly starting and stopping pluggable transport processes when the bridge settings are reapplied in quick succession.