#473 allow scripting of PyDev perspective, not just editors

[Glyph Lefkowitz]

In order to execute a user script in PyDev, you have to open a new editor. But some scripts would be more useful to execute just after starting the workspace, with no editors open.

I'd like to write scripts that can execute in the PyDev perspective, even if no editors are open. There are two particular scripts of this variety I'd like to write: one would be to scan a particular set of directories for new projects and create them without requiring confirmation, another is to open particular groups of files relative to a project.