phpunit builder should (optionally) only check for a return code or make the number of lines for 'OK' message flexible

the problem is that the build execution output grew when other plugins are added.

009-09-13 01:03:56,970 INFO [BAM::Default Agent::Agent:pool-4-thread-1] [PhpUnitBuilder] Build failed since text 'OK' was not found in the last 20 lines of the output.

So even though 'OK' appears it's not in the last 20 lines - we should increase it to say 200...

In PhpUnitBuilder we should use a system property.
private static final int PHPUNIT_FIND_SUCCESS_MESSAGE_IN_LAST = <System.property>;
accordingly.