Improve naming conventions.

* 'get', 'set', and 'modify' are now '#', '#!', and '#@',
  respectively. This is partly for brevity, and partly to
  match the impure connotation of '!' and the "application"
  sense of '@'.

* 'get2' and 'set2' are '##' and '##!'.

* The type suffixes have been expanded because the
  single-letter versions were too opaque. E.g., 'showi' is
  now 'showInt'.

* The v-suffixed functions are now pluralized to reinforce
  the assocation between vectors and plurality. E.g.,
  'showiv' is now 'showInts'.
Add absolute-value functions.
Add 'headTail' and 'transpose'.
Update 'max' and 'min' family of functions.