1.5.2

• TileStrata will now ignore any falsy values passed to .use() instead of throwing an error. This makes conditional plugins in configs a lot cleaner / simpler:

.layer('mylayer').route('t.png').use(cacheEnabled && disk.cache(...))
.layer('mylayer').route('t.png').use(null)
.layer('mylayer').route('t.png').use()
// etc