Version 0.3.0

Enhancements:

* Accepts values for Date, Format, Identifier and Type (complete
coverage of Dublin Core fields 1.1)
* All fields accept multiple values
* Empty meta no longer saved as empty, but deleted; deletes empty meta
written by previous versions
* l10n for default meta values
* Tooltips on settings page
* Detects install, upgrade and downgrade
* More efficient uninstall
* More efficient metadata retrieval

Bug fixes:

* l10n: Bad filenames for pt_PT