ObjFileset defaults to the 'obj' directory in current scan dir

[hanappe]

close #27

The ObjFileset task will, by default, check that the 'obj' fileset exists in the currently active scan directory.

The proposition involves three changes:

• If no 'scan_id' is given, the default active scan will be used. The scan_id can still be set in the configuration file as before.
• The previous default fileset_id has been changed from "data" to "obj"
• This default value of the fileset_id can now be changed in the configuration file (was previously hardcoded)

So if no [ObjFileset] section appears in the configuration file, the fileset /obj will be used. Otherwise this can be changed in the configuration as follows:

[ObjFileset] scan_id = "myscan" fileset_id = "data"

[hanappe]

Replaced by addition of VirtualPlantObj in romitask