Qualified locations

[topnessman]

No description provided.

[wmdietl]

Is this a replacement for #43?
Can you update this PR and make it ready for a review?

[wmdietl]

@lnsun Could you have a look about salvaging some of the work in this PR?
It is useful for PICO and GUT, where you don't need annotations on all types.
Instead of QualifiedLocations this is now expressed with https://github.com/typetools/checker-framework/blob/master/framework/src/main/java/org/checkerframework/framework/qual/TargetLocations.java
However, that annotation is not enforced typetools#1919

Another relevant annotation is https://github.com/typetools/checker-framework/blob/master/framework/src/main/java/org/checkerframework/framework/qual/RelevantJavaTypes.java

[lnsun]

salvaging

@wmdietl OK. I will try to extract works that do not have its counterpart in typetools/CF.