This changes the default for the `last` parameter of various `find`
routines from `0` to `-1`. Previous default prevents limiting the search
to the first character. This is a logic error, as full text search was
performed for 2 *valid* values of `last`: `0` and `last.high()`.
Adds an overload for `initSkipTable` which returns a newly initialized
table. This encapsulates every single usage of a `var`-acting original
func in this module.
Co-authored-by: flywind <xzsflywind@gmail.com>