moai-luaext obeys the MOAI_WITH_* flags

The moai-luaext module obeys MOAI_WITH_* that will enable/disable
individual lua bindings. For instance, it doesn't make sense to provide
lua bindings for SQLite if MAOI_WITH_SQLITE3=0.

Also, added lua-yaml bindings to the luaext module.
luaext builds with luayaml, according to MOAI_WITH_YAML
host-glut obeys MOAI_WITH_* definitions