Improve use of auto-detectable import plug-ins that can be used with or without configuration

[Jari Häkkinen]

I noticed some undesired behaviour with the forthcoming batch importers. I have created a configuration for the sample importer for use with a standard sample import format at our array facility. It works great for us but for other users not familiar to the configured format the configuration creates confusion. Clicking on import and selecting 'Sample importer' as the plugin, the 'File format' option stays as auto-detect. But when the file to be imported dos not match any configuration the wizzard will complain about no matching format found. In this case one would like to end up in the parameter dialog even if no format was matched. The difference is that when a format was matched there is pre-selected values whereas in the case of no format match there is no selected values. As it is now, the user must select 'none' as File format to get to the plug-in parameter dialog.

The issue raises because previously there was only two outcomes, eithet a configuraion was required or not. With the batch importers configurations are optional and therefore the batch importer plug-in should be started even if no automatic match was found.

[Nicklas Nordborg]

I think the annotation importer suffers from the same issue.

[Nicklas Nordborg]

(In [4435]) Fixes #1102: Improve use of auto-detectable import plug-ins that can be used with or without configuration