fix not all model properties getting rendered

- root problem is that the datatype select component
would fail if the data type is not a string
- the user had some properties defined as arrays:
eg: type: ["number"],
- added logic to try/catch the value setting and reset to
string if it errors out.
- also added updated properties iteration to update model
to make sure model properties get updated explicitly during
model save
- add unit tests to cover some of the changed functionality
- fix broken datasource unit test
- fix erroneous response property reference
- fix timeout issue on datasource test spec
- replace missing ds update test
Merge pull request #449 from strongloop/fix/442-not-render-all-properties

fix not all model properties getting rendered