The main change in this commit is to introduce a new BuildHandler
abstraction. A BuildHandler is responsible for producing the metadata
for a build. Two implementations are provided; one for standard builds
and one for incremental builds. This change means that the annotation
processor is no longer concerned with the two different build types
and can use the same logic in each case.
The code for reading and writing metadata files has also been moved
out into a separate class, MetadataStore, to allow it to be easily
utilised from multiple places.
Closes gh-2313
23c175f674