introduce two new actions: include, include-inner

[terryatgithub]

This PR is to implement the requirement of #270 .
Please check it for detailed info.

if any questions pls let me know.
thank you very much.

[terryatgithub]

update:
we've implemented the complicated cascader menu with the new actions include and include-inner. and can not think of other ways to achieve that effect.
so please help to evaluate, thank you very much.

[adamstep]

Hi @terryatgithub . Thanks for the PR implementing these additions. I am not sure if we want to add them to the core Hyperview, I need to take more time to understand whether this is a useful action for general use.

In the meantime, is it possible to add include and include-inner to your app as a custom behavior? I think it should be possible to do it, and you won't be blocked on updates to the core HV library.

[terryatgithub]

ok, Adam, thanks for reply. I can understand it. and i will try the method of custom-behavior.
and maybe later I will also create a demo implemented by include and include-inner for your reference.
thanks so much.

[terryatgithub]

Because of this wonderful realization in #309 by Adam, this PR is not needed anymore.