Log Message:
tcllib: update to 1.21, add examples to package

New in Tcllib 1.21
==================

    Module   Package               New Version   Comments
    -------- --------------------- ------------- ----------
    math     math::changepoint     0.1
             math::combinatorics   2.0
             math::figurate        1.0
             math::filters         0.1
             math::probopt         1.0
    -------- --------------------- ------------- ----------
    mkdoc    mkdoc                 0.7.0
    struct   struct::list::test    1.8.4
    -------- --------------------- ------------- ----------

Deprecations in Tcllib 1.21
===========================

Four packages are stage 2 deprecated in favor of two replacements.
All internal users of the deprecated packages have been rewritten to
use their replacements.

    Module             Package           Replacement      Deprecation stage
    ------------------ ----------------- ---------------- \ 
--------------------------------
    doctools           doctools::paths   fileutil::paths  (D2) Attempts to use \ 
throw errors
    doctools           doctools::config  struct::map      (D2) Attempts to use \ 
throw errors
    pt                 paths             fileutil::paths  (D2) Attempts to use \ 
throw errors
    pt                 configuration     struct::map      (D2) Attempts to use \ 
throw errors
    ------------------ ----------------- ---------------- \ 
--------------------------------