Update to Twisted-15.2.1.

enable registration in the demo servers

Conflicts:
	synapse/http/matrixfederationclient.py

Fix the --generate-keys option.

Fix the --generate-keys option. Make it do the same thing as --generate-config does when the config file exists, but without printing a warning

Clean up some docs and redundant fluff

Federation demo start.sh: Fixed --no-rate-limit param in the script

Remove call to "recently" removed function in mock

The startswith("@") does the job

when someone calls Cache.invalidate with the wrong type.

Change Cache to not use *args in its interface

Make CacheDescriptor cache deferreds rather than the deferreds' values

Merge branch 'erikj/cache_deferreds' of github.com:matrix-org/synapse into erikj/cache_varargs_interface

Merge branch 'erikj/cache_deferreds' of github.com:matrix-org/synapse into erikj/cache_varargs_interface

Three small improvements to help debian package (SYN-420)

Add support for using keyword arguments with cached functions