Changelog voor v0.5.0

Feature: [#31] Automatically install new builds.
Feature: [#34] Support for macOS.
Improved: [#40] OpenLauncher now displays its version in the GUI.
Improved: Improvements for Dutch and Hungarian localisations.
Change: [#39] Rename ‘pre-release builds’ to ‘development builds’ for consistency.
Fix: [#36] Incorrect display of release times.