Add support for (non-PT) bridges

• This adds an additional bridge_lines parameter to runProxy(), containing a newline-separated string of bridge lines.
  • This parameter is nullable (null means don't use bridges).
• The onionmasq backend splits and parses these (throwing the new BridgelineException if any fail to parse), and then feeds them to Arti.
• This is probably of limited use without PT support though, which is coming next!

Closes #53 (closed).