Added "autoclear" setting so invalid values persist

To increase usability, add a new setting that keeps invalid values in the
input field to give the user a chance to correct a mistake. If the user
fat fingers the value on accident and doesn't realize it before tabbing
away from the form field, the invalid value will remain so the user can
correct the value rather than retyping it.

- Added new setting called "autoclear", defaulting to true, to maintain
  existing behavior.

- When autoclear=false, leave invalid values visible so the user can
  correct their mistake.

- Added test coverage for when the mask(...) is first invoked
  (Init.Spec.js)

- Added scenarios to Focus.Spec.js to cover new functionality

- Repackaged the distribution version to include this new feature