Failing code generated when constructor reference uses full package name

[AlecKazakova]

If an output file has two classes with the same name, constructor references for the second time will generate as

::com.example.Foo

which fails compilation

Ideally we can generate an import alias whenever there is a conflict to avoid this:

import com.example.Foo as CEFoo

::CEFoo

[Egorand]

@AlecStrong currently they way to work around this is to manually add an import via FileSpec.addAliasedImport(), as described here. I'll look into making this step automatic.