Add dev script for finding where functions are called from, and finding functions that aren't called at all

Define __repr__ methods for StreamConfig and PaginationConfig

So that they can be used with "%r" log formats.

Implement configurable stats reporting

SYN-287

This requires that HS owners either opt in or out of stats reporting.

When --generate-config is passed, --report-stats must be specified
If an already-generated config is used, and doesn't have the
report_stats key, it is requested to be set.

SPEC-216: Allow users to view the history of rooms that they have left.

the room.

There isn't a way for the client to learn a valid "to" token for a room
that they have left in the C-S API but that doesn't stop a client making
one up.

Print an example "pip install" line for a missing requirement