oid2name : add objects file path

Hello,

This is my first patch to the project.

I noticed that the oid2name tool does not display the file path of objects.

I thought this could be interesting and that others might find it useful,
so I made a little patch to display the full path of objects retrieved by
the oid2name tool. These will be displayed using the -x --extended option.

$ oid2name -p 5435 -x
All databases:
Oid Database Name Tablespace Filepath
----------------------------------------------
16392 b1 pg_default base/16392
5 postgres pg_default base/5
4 template0 pg_default base/4
1 template1 pg_default base/1

$ oid2name -p 5435 -d b1 -x
From database "b1":
Filenode Table Name Oid Schema Tablespace Filepath
-------------------------------------------------------------------
16393 t1 16393 public pg_default base/16392/16393

$ oid2name -p 5435 -d b1 -i -x
From database "b1":
Filenode Table Name Oid Schema Tablespace Filepath
-------------------------------------------------------------------
16393 t1 16393 public pg_default base/16392/16393
16396 t1_c1_idx 16396 public pg_default base/16392/16396

Regards

David Bidoc