problems with long source list

hi

we migrated our build from ant to gradle and now we have problems with the jenkins findbugs plugin
the findbugs step seem to end never and the node were it was build was left in an unusuable state
after long investigation I found out, that the findbugs writes very much into the node log... 1 message with all source search directories for each findbugs warning
because not all files with findbugs warning were printed out, it was clear, that there is a logging issue
this pull request reduces the amount of logging by printing out the list of source folders only once, because in our gradle build, this list consist of all source files (why it didn't found the source is another issue)
another question is, why the pluginlogger from FindBugsPublisher.perform isnt used for logging and instead an own logger is created?
finally, i removed files and added them to .gitignore which are created by mvn eclipse:eclipse

hopefully this will help improving the plugin
we can now use it again

if you have any further question you can contact me (in german too)

best regards