Add functions for range-based for statements.
Rewrite in Google style.
Add SAT_ERROR_MESSAGE macro.
Replace exception messages with the macro.
Replace the exception message with macro.
Replace exception messages with the macro.
Add SAT_ERROR_MESSAGE and Replace exception messages with it.
Merge definitions of basic types and its functions into core.h.
Merge definitions of sequences and its functions into sequence.h.
Move the macro header to bits directory.
Restructure headers.
Remove unused headers.
Add a clause stream operator.
Add sat::WriteInstance.
Fix the bug that sat::ReadInstance didn't catch some exceptions.
Merge branch 'dev'