Integrate ViewpointAdapter and DependentTypes

[jyluo]

to keep opprop/CF in sync and not diverge from typetools/CF

[wmdietl]

The steps we wanted to follow before doing this are documented here:
#69 (review)

[jyluo]

The review notes say

1. raise dependent types to ATF level from GenericATF 2）Merge the two functionalities

I'm unclear on what "dependent types" here refer to.

[wmdietl]

https://github.com/typetools/checker-framework/blob/master/framework/src/main/java/org/checkerframework/framework/util/dependenttypes/DependentTypesTreeAnnotator.java
and other classes in that package.
Viewpoint adaptation and what is called "dependent types" here have similar functionality.
Currently a lot of this is duplicated. This should be unified into one nice implementation.

[wmdietl]

eisop#266 integrates the ViewpointAdapter with eisop.
Further integration would still be good to simplify the code.