Add an agument to set uncompressed

[garyvdm]

I'm using desync to chunk a squashfs image, and so it makes sense to use uncompressed.

I find setting up the the config file to use uncompressed very clunky. I would like it if one could set that the stores in use are uncompressed via the cli, e.g.

desync make --store=/path/to/store --uncompressed ...

I would like to try contribute a patch for this, but would like to check with you guys that you are happy with this before I start working on it?

[folbricht]

The downside of that is that it'll have to apply to all stores in the command-line. That should be fine if documented that way. And as for the option itself, would it be best to make it clear that it's a store-option and name it --store-uncompressed or similar? That's a little more extensible if anything similar is needed later.