Parameterize the release script for gradle command
Parameterize the release script for gradle command

Use the GRADLE environment variable as gradle command. If it is not set,
use ./gradlew.

As a consequence, this command builds with "gradle":
    GRADLE=gradle ./release

While this command builds with "./gradlew":
    ./release

WPO-Foundation/gnirehtet,JonnyShuali/gnirehtet,WPO-Foundation/gnirehtet,Genymobile/gnirehtet,WPO-Foundation/gnirehtet,Genymobile/gnirehtet,JonnyShuali/gnirehtet,Genymobile/gnirehtet,WPO-Foundation/gnirehtet