Support memoized config

[cheton]

React context uses reference identity to determine when to re-render, this PR uses a memoized method to return the previously calculated result to avoid unintentional renders in consumers when a provider's parent re-renders.

[coveralls]

Pull Request Test Coverage Report for Build 32

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.118%

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Totals
Change from base Build 27:	0.0%
Covered Lines:	16
Relevant Lines:	17

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💛 - Coveralls