Fix GSLS optimizer bounds if entries have None

[woodsp-ibm]

Summary

Fixes #94

Details and comments

When the optimizer creates its upper and lower bound arrays, any None entrys are replaced by infinity (i.e. No bound)

[coveralls]

Pull Request Test Coverage Report for Build 6618976410

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.03%) to 90.554%

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Totals
Change from base Build 6573888143:	0.03%
Covered Lines:	6452
Relevant Lines:	7125

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💛 - Coveralls

[ElePT]

LGTM, thanks!