mac custom font fix v2

just truncate name internally as in iPhone to load font with path but you still need to add all fonts to .plist file
another version https://github.com/cocos2d/cocos2d-x/pull/7557 that load font directly by path you don't even need to add it to plist file
merge only one
Why replace ‘Schwarzwald Regular.ttf’ with 'Schwarzwald.ttf '? I can't find it in 'Resources' directory.