Make persp-find-some smarter

[zenspider]

I'm not thrilled with the way persp-find-some works when you're killing off perspectives.

The gist: Let's say you're using this mode (persps sorted chronologically) to do a yak shave and you have several perspectives pushed on the stack. You finish up some of them and start to kill the perspectives. The first time, it uses persp-last to switch to the last one you were on. That seems fine. But after that, persp-last is nil and it goes to (car (persp-names)) instead. That doesn't really match the workflow for this mode and should be something a bit smarter (newest, or persp-last should maintain a stack, or something).

Originally posted by @zenspider in #87 (comment)

[gcv]

I wonder if this might be the excuse needed to stop using frame parameters to store state and switch to a global hash table indexed by frame (id). Frame parameters cause other problems, like the one #86 attempts to address. It's kind of a big change, though.

[gcv]

Looking at this and thinking about it... doesn't (persp-names) respect the sorting order? I just tried it, and perspective killing proceeded in pop-the-stack order. IOW Perspective currently behaves just like description suggests it should, at least for the yak shave workflow. Maybe I'm missing something?

[gcv]

Let's reopen if this is still something we need to look at.