Nx id13 bug

Two bugs related to getting the full URI for lima data:

1. Writer blocked (inf loop) when it could not find the default attributes leading to the lima dataset

2. I was retrieving the URI for each image instead of each file (yep)

Also I am trying to get the file lock now when opening the lima file to make sure lima is really done with this file.

In the (near) future it won't be necessary to open the lima file at all, but ok, lets fix this anyway.