v0.6.7

Feature:

• Refer to query and command query with {q} and {cq} in preview command.
• Support fzf's theme strings, e.g. bg+ for current line's background.
• Support customizing styles of query strings.

Bug fixes:

• skim would crash if multiple CJK items are matched in an OR query.
• SKIM_DEFAULT_COMMAND not correctly recognized in sk-tmux
• UI responses are slow on large input