module to replace matched text by the external command result

Changes for 0.9902 - 2023-11-19T01:51:47Z

• make --fillup to work with or w/o --discrete
• replace tr by perl, because tr on ubuntu does not convert non-ascii chars
• introduce --squeeze option
• use "gpty" command to make Japanese manual desumasu-style.
• extract pod part for i18n documentation
• change option name --blockmatch -> --blocks