pom.xml: update to killbill-oss-parent 0.3.6

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
.idea: don't wrap xml elements

This is mainly to reduce code churn with the sortpom plugin.

It doesn't look like we can force idea to expand <foo /> into
<foo></foo>, so we will still have some churn.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
.idea: define fast and slow groups for TestNG

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>