Extend Eclipse perspectives to fit operational needs

[berryma4]

1. Configurable directories to read in perspective xml files
   • maybe separate user directories vs. system or shared, I was thinking official operations perspectives, and special user defined perspectives
   • maybe allow perspectives (xml files) to be double-clicked?
2. Perspectives should be able to include BOY screens (views with inputs)
   • How would we promise BOY files would be available?
   • Should we get rid of BOY run mode in an editor?
   • Should we allow editors to be saved to a perspective?
3. Would we make our own gui viewer of available CS-Studio Perspectives?
   • Some way reduce clicks

Use cases:

1. User opens "tuning perspective", all relevant BOY screens open in the correct positions.
2. User has "many" open screens, he/she saves the perspective to open on another computer, or at a later time (returning on shift).

[kasemir]

Fundamentally, that's all great. I'm sure nobody would oppose.

Technically, the Perspective only handles "Views".
After moving to E4, one could look at maybe saving/restoring the model state instead of using perspectives at all. Or continue w/ perspectives, but turn most of our "Editors" into "Views", so they're handled by the perspective.

[berryma4]

will be addressed in #544