feat(lua): interrupt and sleep Lua APIs

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(lua): add has_metavar method

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/expr_lt): fix bug when using hash codes

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(lua): add splay_maps to the Lua API

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(lua/splay_tree): for_each method was crashing if the map was updated during for_each

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
style(lua): ignore bogus warning

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