Added an option to copy parts of the log to the clipboard - either just a single line or the line and all its children (the block).

If the block is large (over 64K), then the app will also display its size on the right-hand side on the menu. The neat thing is that this information is readily available in the log index, so this requires no log scanning of any kind or no interim memory allocations. Basically, it's as O(1) as it gets.

Will be in R75.