Added Checkstyle 10.17.0

Added Checkstyle 10.16.0

Added Checkstyle 10.15.0

Fixed incorrect icon sizing on some platforms (#637).

Updated icons to match new UI style

Another fix for Gradle

Attempt to fix intermittent Gradle failures by explicitly declaring i…

…mplicit deps

Ensure third-party classpath is reloaded by extracting common reset c…

…ode to a single class (#630)

Fix exception when opening modal dialogues

Drop LGTM badges as it has been absorbed by GitHub