v0.8.1

Feature:

• #63 could save to and read from history for query and command query via --history and --cmd-history
• #273 inline-info now has spinner
• #276 new action: if-non-matched will execute if non of the items matches
• reduce memory footprint
• #248 implement {n} placeholder, used to refer to current items's index(zero based).

Bug fixes:

• PR #279 exit gracefully on SIGPIPE error. (e.g. Ctrl-C on pipes)
• #276 execute panic on zero results
• #278 NUL character not working in preview command
• handle print0 correctly in filter mode
• Preview's fields now based on original text, not transformed.
• #295 skim not exits sometimes (occasionally happens on Ubuntu)