v0.12.9

• change gita ll -n to gita ll -C for disable coloring
• add gita color set <situation> <color> command to change the coloring scheme of local/remote relationship
• add gita freeze to show URL, name, and path of all repos
• add gita clone <config-file> to clone repos to cwd
• add gita shell command to run shell commands
• display help message for most commands (use description instead of help for subparser)
• add gita group rmrepo command to remove repo(s) from a group
• display tag name instead of HEAD when a tag is checked out
• fix traceback when deleting current context