Upgrade version code

Fix Preview Image Error

Update Default UTheme
Fix a text format bug

Fix a bug that cause the crash when exiting editor.

Compatible with UE4.20

Merge branch 'master' of https://github.com/Jack-Myth/UE4EditorCustomize

Merge branch 'master' of https://github.com/Jack-Myth/UE4EditorCustomize

Update README.md

Create README.md