• Fix: Fix some bugs.
• Del: Remove extra package now.
• Add: Adds UsageFn for customizing usage.
• Mod: Replaces NeedArgs with NumArg.

Initializes the repository, and implements many important features.

• Add: Prases flags base on golang tag.
• Add: Supports almost all basic types, slice and map as a flag.
• Add: Fuzzy matching for suggestion.
• Add: Supports command tree.
• Add: Pretty output for usage of command.
• Add: Supports any type which implement cli.Decoder as a flag.
• Add: Parser for flag.
• Add: Supports editor like git commit.
• Add: Rich examples to help other quick start.