v1.6.10

• Added an optimization to further reduce flicker when re-drawing the prompt.
• Added a user_data.shared_user_data table to allow linked argmatchers to share data with each other while an input line is being parsed (see Responding to Arguments in Argmatchers for details).
• Fixed #579; popup lists could accidentally truncate text in the first column when there's only one column.
• Fixed #576; setup exe doesn't remove old uninstall exe files.
• Fixed #575; error when color.executable is set and color.unrecognized is not (regression introduced in v1.6.2).