Add whole-words? option for generated patterns

Add whole-words? option for generated patterns

This option causes patterns to require a word boundary on either end of
the match. For instance a pattern built from:

  [ "foo" "bar" "baz" ]

Will create a match against the following strings:

  "foo is a metasyntactic variable"
  "sometimes we use baz"

but will not create a match against the following:

  "food and nutrition"
  "clubs and bars"