Version 1.3 released

Changes from previous version:

• New feature: localization. The english (US) and italian localizations are available. More localizations will be available as soon as possible. Contact me if you want to contribute to the translation.
• New: custom color option for highlight colors.
• Export to HTML: added hyperlinks between objects in relation between them.
• Fixed bug: deleting an object, its relations were not deleted with it.
• Minor bug fixes and code improvements.