single-quoted strings and redundant curly braces around a hash parameter

Previously, quoting an array fell back to `inspect`, which is ok for
strings, but not good for BigDecimals, for instance.

[ fixes #252 ]

This reverts commit 067ce522.

Potentially addresses issue# #167
Annotate_model_file is called automatically on all files in models directory and does not check if model contains SkipSchemaAnnotations tag.