expanding flags

[dan9186]

• add staged flag to diff cmd
• add prune flag to fetch and pull
• add tags flag to push cmd
• add branch flag to status cmd
• add remote rename
• add update flag to add command
• add move flag to branch command
• add all flag to fetch command
• add ff only flag to pull and merge command
• add show current flag to branch cmd
• add allow empty flag to commit command
• add max count flag to log cmd
• add continue flag to merge command
• add follow tags flag to push cmd