Remove parsers directory

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Move sexpr/format/options to util/sexpr (reason: circular dependency between util and numerics lib), now numerics depend on util, and sexpr depends on numerics and util. Add scanner to frontend.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add missing tokens

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add missing files

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Fix clang warnings

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Remove option name::separator, it can't be configured during runtime

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>