Fix NPE when orphaned network request tries to access views.
Increment plugin version, and tidy build.gradle.
Squashed 'lib-holocircularprogressbar/' content from commit 67ec22d

git-subtree-dir: lib-holocircularprogressbar
git-subtree-split: 67ec22dd844734be1d087a577c5d44f401b8993b
Merge commit 'b30d4da51c919cbd3a55f15a16f8342016a85031' as 'lib-holocircularprogressbar'
Integrate circular progress bar lib into app project.