Update used classes based on type arguments

[LoiNguyenCS]

No description provided.

[LoiNguyenCS]

Professor,

This is the PR to fix a bug of Specimin.

Currently, there is a bug where Specimin fails to consider unsolved types if those types only appear as type arguments. For example, Specimin will overlook unsolved types BigTree and SmallTree in Map<BigTree, SmallTree>.

This is one of the bugs that I have figured out while trying to make Specimin work for AnalysisResult.java (but right now there are still more bugs to fix before that happen)

[LoiNguyenCS]

Professor,

I have updated the documentation. I've tried to keep it shorter than the explanation I wrote in this PR. Please take a look. Thank you.

[LoiNguyenCS]

Professor,

I have updated the codes so that we don't have to call two methods together every time we update the list of used classes based on the type of a used element. I have decided to use "element" instead of "member", because in the beginning of TargetMethodFinderVisitor, a member is defined to be a method or a field only.

[kelloggm]

Thanks! I think this design is much cleaner.