Add imports for inner items of arrays/maps in composed schemas

[zippolyte]

For typescript at least, we need to import the inner items of complex types of the composed schemas. This PR adds it.
There might be a better/cleaner way to do this, I'm using the fromProperty method to re-use existing algorithm and have the complexType property and import them all.
Please advise if it should be done another way.

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[zippolyte]

@wing328 @jimschubert if you could have a look at this 🙂

No sure why travis and appveyor have different behaviours with the generation, looks like there is generate-alias-as-model set to true in travis, because travis generates the set of oneOf as [Apple, Banana, Grapes] while appveyor generates it as [Apple, Array<Grape>, Banana] for the same test (in RubyClientCodegenTest.java:367)

[zippolyte]

@wing328 @jimschubert, any ideas on this ? Why the different CI don't generate the same things for ruby unit tests ?

[therve]

@wing328 @jimschubert @cbornet @ackintosh @jmini @etherealjoy @spacether we fixed the CI, thanks for taking a look 🙇 .

[wing328]

LGTM. Sorry for taking so long to review as there are just too many PRs.