Added support for showing a list of open and/or modified buffers

[bjorn-ove]

I optimistically add this pull-request to show why I created jmacdonald/scribe#16. I have been sitting on and using this code for my own work daily since August 2018 and think it is stable.

The reason I created this PR now is that I noticed #141 and wanted to save @jmacdonald some work if possible.

I optimistically updated Cargo.toml with the new version of scribe, but will not be able to do the same with Cargo.lock until it is actually pushed to crates.io.

I fully understand if this feature is already being implemented in a different way and won't take offense if the PR is rejected. I am also happy to make adjustments/additions to make it comply.

[jmacdonald]

Hi @BearOve!

Thanks for this PR. I have definitely been thinking about how to handle open buffer navigation for some time. I'd like to take it in a different direction than the search/select approach, since I tend to keep very few buffers open at once, and would like to find a more suitable UI. I still need to do some UX designs around that, but I think it'll be a decent amount of work, since it'll deviate quite a bit from the other bits of UI.

That said, your point about using this PR as an example for the workspace buffer iteration work you've done is great. I'll set aside some time to review that PR and provide some feedback there; making the workspace iterable is a nice addition. 👌

[bjorn-ove]

For me, the search part of it is essential as I often keep 10+ files open, and arrow navigation doesn't cut it. I often end up finding one or two letters in each buffer I switch between to quickly switch with very few button presses.

A side-note in case you didn't actually try it. All the open buffers are visible the second you open the search select bar. It is not like regular files where it starts up empty.

Anyway, perhaps your way is better once it is ready. I won't know until I try. Worst case, I'll continue running off the fork.

[jmacdonald]

@BearOve one of the things I'm particular about is not keeping many buffers open; I'm easily lost, and so I try to close other buffers as I drill into a particular bit of functionality (this was the justification for the buffer::close_others command 🙂).

That said, I'll give this implementation a shot; you might change my mind. 😇