add validity check for JSONObject constructors

[Madjosz]

• fixes JSONObject constructors do not check for non-finite numbers #713
• document JSONException in JavaDoc
• remove unused Comparable boundary to reuse GenericBean in test

[stleary]

@Madjosz Your branch may be out of sync due to recent changes in JSONObjectTest.java.

[stleary]

What problem does this code solve?
Numeric inputs in JSONObject constructors should check for validity.

Risks
Low

Changes to the API?
No

Will this require a new release?
No

Should the documentation be updated?
No

Does it break the unit tests?
No, new unit tests were added

Was any code refactored in this commit?
A few minor refactorings unrelated to this commit are included.

Review status
APPROVED

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