persist log since time && dynamic routes adding

[saiwl]

1、Logspout collects container log with sincetime. Once the process exits and starts again, there will be log loss before logspout restarts. So I wonder that logspout can persist the sincetime, then the process can restart with the persistent sincetime and will avoid losing logs.

2、Dynamic routes adding. When a new container start, logspout can get the specific env which describes the route wanted. And then the route can be added by itself.

If someone think these features are useful, I will work on it.

[pikeszfish]

+1