This reverts commit c3f9d8e4.

handle m.room.aliases for id<->alias mapping; remove local_storage map; stop local echo flickering by removing opacity transition for now; implement /join

Merge branch 'captcha' of github.com:matrix-org/synapse into develop

Captchas now work on registration. Missing x-forwarded-for config arg support. Missing reloading a new captcha on the web client / displaying a sensible error message.

Added a captcha config to the HS, to enable registration captcha checking and for the recaptcha private key.

Modified matrixService.register to specify if captcha results should be sent with the registration request. This is toggleable via useCaptcha in register-controller.

Validate power levels event changes. Change error messages to be more helpful. Fix bug where we checked the wrong power levels

BF: tab completion did not work with commands. $scope.input contained only the typed chars not the result of the completion.
Needed to fire an event so that ng update the input model