Separate intensities for sum and profile integration

Closes #591

See merge request !34

- Shorten column headers

- Correct overwriting of IntegrationFlag after it has already been set

Remove redundant peak metadata

Closes #469, #576, #597, #598, and #599

See merge request !33

Refactor peak exporting

See merge request !32

- destructors for XComboBox objects to prevent segfault on refresh
- Remove unnecessary field from PeakExportDialog

- Made MtzExportDialog applicable to all export format
- Removed many unnecessary menu entries
- Fixed MtZExportDialog visuals
- Fixed several dialog and exporter bugs
- Remove merge computations from all GUI classes, they are now handled
  by PeakExporter

Allow user to visualise changes in convolver parameters

Closes #590 and #572

See merge request !31

Fix cursor mode bug after line plotting

Closes #589

See merge request !30

Update tutorial

Closes #558

See merge request !29