computeCurrentPeriodsHighestCounterValue() method should increment currentPeriodsCounter in case parent raw file==null and the file with the last index is compressed

Suppressed support in ThrowableProxyUtil.

Updated according to Cekis suggestions.

Correct 0.9.30 version in @since tag

Three fixes from static-analysis tools.

Reviewed changes.

Also added two tests that are only executed if running on Java 7.

Two fixes from static-analysis tools.

Reviewed changes.

Remove unnecessary interface modifiers.

Checked the changes.

Adding support for Throwable.getSuppressed().