listen for model-updated from fields, and fix `debounceFormatFuncti…

[zoul0813]

• Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Fixes the bug reported in #554

• What is the current behavior? (You can also link to an open issue here)
  'model-updated' is not called when using 'fields', but works when using 'groups'

• What is the new behavior (if this is a feature change)?
  'model-updated' is emitted for both 'fields' and 'groups'

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

No

• Other information:

• Refer to @model-updated not working in newer versions #554 for details

• Also changed 'debouncedFormatFunction' to be 'debouncedFormatFunc' to follow naming convention of 'debouncedValidateFunc' and 'formInput' already used 'debouncedFormatFunc' (likely with warnings/errors since it was declared incorrectly).

[coveralls]

Coverage remained the same at 89.916% when pulling 7ad1fca on zoul0813:feature/554-model-updated-fix into a484031 on vue-generators:master.

[coveralls]

Coverage remained the same at 89.916% when pulling 7ad1fca on zoul0813:feature/554-model-updated-fix into a484031 on vue-generators:master.