State Management Flexibility

[mgcuthbert]

This is a fairly simple PR that just gives a little bit of flexibility to the replication module allowing users to do two things:

1. Download a single replication file at a time
   This just gives added flexibility and very useful if you are either debugging a specific issue with replication or simply controlling specifically the replication process.

2. Allow a user to set a custom server state file locally instead of depend on the remote state.
   This again allows great flexibility in debugging issues, as you can replicate up to a certain point and by setting your local state file and the new custom state file you can replicate only between two points in time.

[migurski]

I’m about to release this in version 0.48.0; if there’s any documentation appropriate for the Detailed Usage wiki can you add it there? Thanks!