Support passing parameters to LockingCache

[tmcw]

Without doing this, you can't use tilelive-mapnik for anything faster than minutely updates (which is what I'm trying to do)

[yhahn]

Not sure this helps but in TileMill we include an updated time as part of the URI query string effectively using a new map whenever there is an update:

https://github.com/mapbox/tilemill/blob/master/servers/Tile.bones#L29-48

[strk]

I'm in need of LockingCache parameters too. Specifically I'd like to be able to control cache timeout and to stop clearing each tile cache as soon as used (which defeats the purpose of a cache, doesn't it ?).

See CartoDB/Windshaft#32

Will probably file another ticket for this.

[springmeyer]

Timeout can now be set in the locking cache constructor after #57. It is not exposed via the URI query string yet. We can consider doing that if needed. In the meantime this ticket does not seem actionable, so closing.