Expressive simulation pattern generation

[lee30sonia]

This PR mainly implements the pattern generation algorithms in the paper [1], but it also:

• Implements ODC computation for incomplete simulation signatures and pattern observability checker in dont_cares.hpp.
• Solves some bugs/issues in incremental simulation with partial_simulator and ODC consideration in circuit_validator.

[1] Simulation-Guided Boolean Resubstitution. IWLS 2020 / ICCAD 2020.

[coveralls]

Pull Request Test Coverage Report for Build 156651505

• 184 of 260 (70.77%) changed or added relevant lines in 6 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 79.961%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
include/mockturtle/io/write_patterns.hpp	5	10	50.0%
include/mockturtle/algorithms/dont_cares.hpp	34	51	66.67%
include/mockturtle/algorithms/pattern_generation.hpp	110	164	67.07%

Files with Coverage Reduction	New Missed Lines	%
include/mockturtle/algorithms/circuit_validator.hpp	3	85.04%

Totals
Change from base Build 155308794:	-0.2%
Covered Lines:	9110
Relevant Lines:	11393

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💛 - Coveralls

[hriener]

Thank you. Looks good!

One minor comment: Could we move the member function write_patterns into its own file in the directory io and provide two implementations of it? The first could write to an output stream and the second could take a filename, open a file stream, invoke the first implementation, and then close the stream?

[hriener]

Thanks!