Adding optional dependencies to install proSVD/bubblewrap, and fixing imports to run bubblewrap demo.

[pgupta29]

This was tested on Ubuntu and Windows.

[coveralls]

Pull Request Test Coverage Report for Build 5834783238

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.08%) to 80.443%

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Totals
Change from base Build 5797436183:	0.08%
Covered Lines:	1016
Relevant Lines:	1263

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💛 - Coveralls