Use p2.inf for configuring ini files

For awhile Gumtree was using the root file mechanism to store configuration (*.ini) to launch Gumtree (http://help.eclipse.org/indigo/index.jsp?topic=/org.eclipse.pde.doc.user/tasks/pde_rootfiles.htm).

It has become increasingly difficult to continue this way, because we need six times more artifacts to manage if we support 32/64-bit Windows, Linux and Mac.

Another way to manage configuration is via the PDE .ini modification mechanism, see:

• http://stackoverflow.com/questions/4431967/eclipse-p2-alternative-for-custom-install-handlers
• http://help.eclipse.org/indigo/index.jsp?topic=/org.eclipse.platform.doc.isv/guide/p2_actions_touchpoints.html
• http://wiki.eclipse.org/Equinox/p2/Customizing_Metadata
• http://svn.objectteams.org/ot/trunk/src/plugins/org.objectteams.otdt/META-INF/p2.inf (example)