overview of key- & mouse- bindings? #555
Description
Hi! I am new to this library and like a lot about it immediately, but my initial experience has been a lot of confusion trying to figure out the default key- and mouse-bindings, so I would like to suggest and request a short and prominent explanation in the README.md and/or wiki about what the various key- and mouse-bindings do, for new users
First I was surprised by not being able to quit with 'q' or 'ctrl+q', and eventually found by searching through the source code that I could use the escape key (d'oh, I should've guessed that, but am actually not used to any program which uses that key to exit...). Next I wanted to figure out how to zoom, and initially thought of drawing a rectangle around an area of interest, which seemed to do nothing (although later I discovered that dragging can pan if zoomed-in). While trying to figure that out, I discovered that I can draw a trend line with ctrl+click, and that with shift+click I can highlight a time interval, although I don't really understand the utility of that, or if it's the basis for doing something else (e.g. somehow zooming to the extents of that interval?).
I tried consulting the wiki, initially checking under "features" and "intro tutorial", but nothing pertinent is mentioned, except a note in the former that it isn't necessary to manually set up keybindings (but is there an easy mechanism to do so, if desired?). Eventually I found a section called "keys" for some reason filed under "snippets", which just enumerates: Esc, Home, End, g, Left arrow, Right arrow. Ctrl+drag. That is something I guess, but "shift+click" - which I am still wondering about - isn't listed, and the keybindings which are listed aren't described, so for example I so far haven't been able to figure out exactly what (if anything) 'g' does, although in the source code I can see it mentioned that it has something to do with clamp_grid, whatever that is.
Knowing these bindings is essential for basic usage, and documenting them could help to ease the learning curve for new users checking this library out, thereby hopefully retaining more of them and attracting more open-source participation/contributions.