Update README.md

Add sections for authors & dependencies
Update dependency versions
Use new meeting scheme for membership status
Clarify meeting requirement string
Update versionCode for release v2.2.5
Merge release v2.2.5 from branch develop
Use build configs to make safe screenshots easier
Permanently deprecate original Alumni Mode
Screenshots for release v2.2.5
Update Gradle plugin to 0.13.0; restore original string paths
Update helpful links
Refactor WebFragment
Open forms in-app via WebFragment.
Update version code for release v2.3.0