Moved all automatic connection logic into poller.

...r-api/src/org/briarproject/api/plugins/PluginManager.java

...-core/src/org/briarproject/plugins/PluginManagerImpl.java

briar-core/src/org/briarproject/plugins/PluginsModule.java

briar-core/src/org/briarproject/plugins/Poller.java

briar-core/src/org/briarproject/plugins/PollerImpl.java

briar-tests/src/org/briarproject/RunAction.java

...s/src/org/briarproject/plugins/PluginManagerImplTest.java

briar-tests/src/org/briarproject/plugins/PollerImplTest.java

...c/org/briarproject/transport/TransportKeyManagerTest.java