v0.2.2 includes updated support for renaming message keys.

This feature was lacking in functionality & unsatisfactory so I fixed it up to be more convenient.

- Renaming the current key in the editor will now work as expected.
- If you try to rename into a key that already exists then it will revert to the last name and displays a warning notification that will inform you of this.
- When a renaming occurs it will now go through every entry with the old key name in the next entry data and update it with the new key name.
- Now includes project file versioning to make updating easier to manage in the future.

In the example capture above I tried to rename "demo_introduction_1" to "demo_introduction_3" which already exists, so it names it back into "demo_introduction_1" and shows a warning symbol next to Key Name. When I click on this warning symbol it will show this message describing the issue.