* Add macro to disable linear solver for development
* Move new_* and add_* to header
* Add ref_vector_core::push_back(ref<T>&&)
* Attempt to simplify lifetime handling
* Make operator bool() explicit
* clause improvements
* display boolean assignment
* clause::resolve
* bug fixes
* more fixes
* final case of backtrack
* Extend search state by boolean literals
* Only resolve against positive equality
* mk_dep_ref
* Make clause non-owning
* scoped_clause
* Use scoped_clause
* minor
* scoped_ptr move assignment
* WIP: internal handling of disjunctive constraints
* leaf_value
* disjunctive constraints continued
* Fix bool_lit
* Actually add constraints to storage
* Some fixes
* more fixes
* constraint should have a bool_lit instead of a bool_var
* propagate(bool_lit)
* updates
* interface changes
* small fixes
* Make sat::dimacs_lit's constructor explicit
(otherwise, calling operator<< with sat::literal is ambiguous)
* Use sat::literal
* Print test name at the beginning
* Convention: constraint corresponds to the positive boolean literal
* Make constraint ownership more explicit
* clause stores literals
