Updated baseline

1.538 is over 13 months old and tests cannot even be run on Java 8. Updating to the next newer LTS.
I will be glad to have wiki page where core version critical changes related to plugins will be tracked.
For example:
``1.554.3 && 1.557 - Fixed java 8 support.
X.XXY - Finally fixed @DataBoundSetter
X.XXX - added @DataBoundSetter
```