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* Large internal rework - introduced update-dependencies for values and
selected meta-values (selects, minimums, maximums, steps etc).
* Added MutaSources as non-UI MutaProps for supporting internal dependencies
* Added HTML type of value (read-only)
* JS client now works with single state-store (Vuex)
* MutaSelects removed - this functionality is now replaced by more general
update-dependencies through MutaSources. This breaks compatibility with 0.4.x