core: fix broken travis build
mylang: simplify parse <-> runtime interface (handling of bindings)
(minor) mylang: __prepare__ -> __my_prepare__
util: fix a stupid bug in InstanceBoundTypeMixin
util: add unique_values: filters unique values from (key, value) pairs
(minor) core: nothing significant at all
core: inherit options from base modules

Also use option_types list of pairs as a keyword argument for
metaclass instead of optypes list