Feature request: Add copy of current problem

[thomas-maeder]

When composing a problem, it is helpful to keep "snapshots" of some stages of the composition process.

This could be achieved by

• adding a copy of the current problem
• switching to that copy for continuing

[dturevski]

There are already several ways to do this in 0.13.6 1) "File" - "Save template": all new entries will be a copy of the current entry (template) 2) In the problem list (bottom right) right-click and select "Copy" to copy an entry. Later right-click and "Paste" to create a copy of the problem. Multiple selection is supported. You can cut and paste to reorder problems in a collection. You can copy and past between several instances of olive to compile collections. You can copy and paste between olive and yacpdb (they have same format).