Fixed a bug in LinearSolver. Basically, when solving integer inequalities a solution with x >... should have the RHS rounded up. This also called for changing the behavior for solving integer equality comparisons, which haven't been used yet so it doesn't affect anyone. With integer equalities I no longer divide by the coefficient of the LHS, which means that the solver could return an expr like: c*x = ...
Fixed a bug in type checking solutions in linear solver.
Merge branch 'specialize_branched_loops' of github.com:kree-colemcalughlin/Halide into specialize_branched_loops
Changed type == Bool() to type.is_bool().