Issue #903: Fix for 0.8.2 and JDK8

As gephi 0.8.2 is still based on Netbeans 7.2.1 it suffers the JDK8 starting issue [#229191](https://netbeans.org/bugzilla/show_bug.cgi?id=229191). This patch upgrades to Netbeans release 7.4.