Remove fix-sized literal buffer in bsat2 interface

[lee30sonia]

This PR changes the type of literals in the interface of abc_bsat2 from a fix-sized array to a std::vector to avoid problems with huge clauses.

[coveralls]

Pull Request Test Coverage Report for Build 421613520

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 94.791%

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Totals
Change from base Build 417519609:	0.0%
Covered Lines:	1019
Relevant Lines:	1075

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💛 - Coveralls