Added lazy loading to the MALDI ion table

[Mailaender]

This is meant to improve performance.

[eselmeister]

When opening a file in the MALDI-TOF perspective, the m/z list stays empty. Is that intended?

[Mailaender]

Updated.

[eselmeister]

The lazy modus works now. But the table is not updated correctly, if another mass spectrum was loaded previously.

How to test this:

1. Load e.g. a chromatogram via the data analysis perspective.
2. Then navigate to the MALDI-TOF perspective.
3. Select a scan in the previously loaded chromatogram, it shall be displayed in the m/z list.
4. Then load the MALDI-TOF file. The previously selected scan remains in the list.

[Mailaender]

I removed the broken lazy loading.