New:
- Open a file-selection dialog when an item has two or more file attachments.
Changes:
- Retrieve abstract only when the option is activated in the preference window.
- Show et al. when the entry has three or more authors (instead of five).
- Retrieve item even if it has no authors.
Bugfixes:
- A running instance of Qnotero is activated when a new one starts.
- Missing DLL added to the Windows setup file.