v2.0.0 - Major Upgrade

Install via the attached files or NuGet.

This update brings a lot of changes to the public API. Expect a lot of buil errors on existing code when upgrading.

Beside a lot of refactoring and cleaning this upgrade contains the following changes:

1. Acces to AchievementManager-Singleton-Instance now through AchievementManager.Instance
2. Achievementprogress is now tracked correctly
3. AchievementControl now displays a ProgressBar when Achievements have multiple AchievementConditions to unlock or one AchievementCondition with more than one unlock-count
4. AchievementControl now displays the progress in a X/Y way where X is the current progress and Y is the progress needed to unlock the Achievement
5. Added NeutralResourcesLanguage and CLSCompliant
6. AchievementControl now shows a Timestamp of when the Achievement was unlocked
7. You can now unlock new Achievements which are using old and unlocked AchievementConditions by calling ReevaluateUnlockStatus() on AchievementManager
8. Achievement now has a public method that checks if all AchievementConditions are met and unlocks the Achievement
9. Constructors of Achievement have changed. Optional Parameters were moved to Properties.