java/eclipse: 4.4.2 -> 4.5.1

• Bump to Eclipse 4.5.1
• Switch to using Maven 3.3
• add fix for running Eclipse build for Gtk2 only on a system where Gtk3 might also be installed.
• Details: https://projects.eclipse.org/releases/mars/details
• Bugs fixed: https://bugs.eclipse.org/bugs/buglist.cgi?classification=Eclipse&classification=RT&product=Equinox&product=JDT&product=PDE&product=Platform&query_format=advanced&resolution=FIXED&target_milestone=4.5.1

PR: 203689
Submitted by: Jimmy Kelley <ljboiler@gmail.com> (maintainer)