Add highlight_keyword, highlight_builtin, highlight_command for consistent formatting

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add methods for creating infix, prefix, postfix operators in the frontend object

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add iterator for traversing local objects (i.e., ignores objects defined in ancestor environments)

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Rename files sets.h and maps.h to expr_sets.h and expr_maps.h

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Move auxiliary files away from kernel

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Delete obsolete function continue_on_violation

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

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Move pretty printer to frontend. Add support for mixfix pretty printing

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Move pretty printer to frontend. Add support for mixfix pretty printing