Use <Leader>e for BufExplorer

vim-vinegar lets me use - to launch netrw and it's consistent with
netrw. That makes <Leader>e for netrw redundant. Use it for BufExplorer
instead (especially since changing my leader makes it harder to hit:
<Space>be is much harder to hit than \be).

It would be neat to split for netrw (and use VinegarUp if possible for
my split window), but that's used for golden-ratio which I use more. I
don't know if I've ever used that map in its previous form.
Clean up visual and normal & maps

I sometimes get confused between these and the built-ins. Adjust them so
they all make sense to me.

& is the flag meaning use the same flags as last time, so commands that
use & should always re-use flags.

Make g& work on visual selection.

g& and && on visual selection are very close, but g& use the current
query (which may have changed).
Make togglequickfix maps more consistent

Use <Leader>w as a prefix for toggling windows. Also do the same for
preview window (although there's no open).

I use <C-w>w a lot, so add a <Leader>w map for that.
Use more unique map for InfoStatusLine: <Leader>si

Add an i on the end of the map so there aren't weird conflicts with
itchy.
Add some prototype code changing maps

Should these be an ftplugin?
They're not great.
Update my code maps to use justinmk's transposing

I use argumentative for arguments and this transpose option seems to be
a pretty effective solution.

Use dt/dT for generic transpose.

Source:
https://github.com/justinmk/config/blob/31135cde3882ded0a08ac4ef2bae6568adff80a6/.vimrc#L876
Maintain cursor position in transpose map

Improve the transpose map by maintaining cursor position.