move Eclipse feature maven builds into feature projects

(Suggest we do this after 2.2.2 release) The current Eclipse update site has one ant build script in the update-site project which builds the features and the update site. This Jira is to move the feature builds to the feature projects. This will allow them to be built when the Features are updated. The Eclipse Update site will have multiple features - some from sandbox projects - which could be on a different build / version schedule, and this change will support that. After the change, the update site will only build the update site itself, copying any updated (new version) feature jars into its own project (where they will be stored in SVN and used for subsequent builds - because the update site will hold previous released "versions" of the features.