Add install configuration to CMakeLists.txt.
Rename unit test sources as Google C++ style.
Rename name of unit tests as it's filename.
Merge branch 'google_style_unit_test_name' into dev
Remove a meaningless unit test for test::SATFixture.
Rename a unit test list file.
Rename sat::Variable to sat::variable_t.
Rename sat::ClauseList to sat::clause_list_t.
Rename sat::Clause to sat::clause_t.
Rename sat::BasicOccurrenceList to sat::basic_occurrence_list_t.
Rename sat::OccurrenceMap to sat::occurrence_map_t.
Rename sat::Instance to sat::sat_instance_t.
Rename type names to its on C++ type name style.

Type names declared by typedef/using statement can not declare forward. It
needs to distinguish class from type name.
Add a constructor for a comparer and a hasher for sat::Literal.
sat::default_literal_comparer: Change to a constexpr instance.
Add sat::default_clause_pointer_comparer.

And replace default sort order of sat::basic_occurrence_list_t to using it.