Support arbitrary orders for column highlighters (it was previously
failing when column highlighters were not applied in column order).
Fix show_matching tab handling at the same time (horizontal scrolling,
tab characters and show_matching were behaving badly).
Window highlighting now runs user highlighters, then built-ins for each
phases, instead of running all phases for user highlighters, then all
phases for built-ins.
We now consider unprintable character to be 1-column width as we know
we will display them as "�".
Fixes#1615Fixes#1023
Instead of highlighting full lines and then trim them to make them
fit in the window, highlight only the visible portion, and rely on
the compute_display_setup system introduced for wrapping to setup
our buffer range correctly
Client quitting no longer immediately unwinds, client is just pushed
for deletion until we get back to the main loop, similarly to what
happens for buffer and window deletion.
