Release 1.9.0

• New libraries: (lispkit sqlite), (lispkit combinator), (lispkit system os), (srfi 195) and (srfi 196)
• Renamed library (lispkit iteration) into (lispkit iterate)
• Extended library (lispkit date-time) with procedures date-time-add, date-time-add-seconds, date-time-diff-seconds, date-time-in-timezone, date-time-same?, date-time=?, date-time<?, date-time>?, date-time<=?, date-time>=?, and date-time-hash.
• Extended library (lispkit core) with procedures thunk, thunk*, define-values, and apply-with-values
• Extended library (lispkit string) with procedures string-normalize-diacritics and string-normalize-separators
• Extended library (lispkit dynamic) with procedures unwind-protect and try
• Extended library (lispkit control) with procedure letrec-values; define-values can now be used wherever define can be used.
• Extended library (lispkit system) with procedures home-directory, system-directory, path-extension, append-path-extension, remove-path-extension, file-readable?, file-writeable?, file-deletable?, directory-readable?, directory-writeable?, and directory-deletable?.
• Extended library (lispkit draw) with procedures set-image-size!, bitmap-size, bitmap-pixels, bitmap-exif-data, and set-bitmap-exif-data!
• Support for timeouts in procedures handling HTTP ports in library (lispkit port)
• Small tweaks to library (lispkit csv)
• Library (lispkit box) now supports multi-value boxes
• New sample code Covid.scm, including data up until June 19, 2020