purge ThreadSafeExecutor to wok.core
:white_check_mark: rewrite CliOption to follow new rules
:white_check_mark: remove declarations of import of Reader/Writer in Wok.scala
:white_check_mark: Specification change: all shortcut methods in Wok should be accessible with accessor style
:white_check_mark: remove import declaration of csv.Row in Wok.scala
:racehorse: reduce accesses to InheritableThreadLocal