feat(util/list): filter template

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(util/list): map_append template

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(util/name_set): add mk_unique (with respect to a name_set)

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/tactic): add focus tactical

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
doc(library/rewriter): add doxygen annotations for rewrite_* funcs
chore(.gitignore): update .gitignore
refactor(library/rewriter): move apply_rewriter_fn into rewriter.h
feat(library/rewriter): implement depth RW