Rename ui.c:request_view_update()

To ui_view_schedule_update()
Extract functions in main_loop.c

should_process_reloads_of_views - Checks whether views can be reloaded
    in current state of the application
process_reloads_of_views - processes reloads of views
Change function names/comments in main_loop.c
Implement better view update scheduling
Add filelist.c:redraw_view_imm()

Updates view immediately on the screen (redraws file list and cursor).
Don't update internal name after rename

It's not getting drawn anyway, so it's completely useless.
Add scheduling for full view reload

E.e. load_dir_list(view, 0);
Better handling of scheduled operations
Fix view update after :restart in some cases

Thanks to filterfalse.
Do full update at the end of :restart
Add hack to prevent flickering of title line

It's in an ugly hack to avoid flickering of top line of the current
view.  We need attributes colors recalculated correctly before applying
them, otherwise color changes twice on the screen.  Need to generalize this
by updating all color pairs that we can, or that depend on group, whose
properties are changed. */
Do not reset window layout on :restart

For this ignore number of windows stored in vifminfo when
re-reading it.
Add comment to cfg/info.c:read_info_file()

And an empty line after its declaration.
Pass pointer to &cfg to reset_status()
Update initial lines&columns on :restart

This prevents UI being redrawn for old size of the terminal first
and for its current size second time.
Use constant for name of builtin color scheme
Do not postpone redraw after :restart

Also don't reload file lists.

This causes less flickering in the terminal.
Document glitches and flickering fixes better
Complete ugly hack to avoid flickering

Didn't always work, made it better, but not perfect.
Do reset color scheme to default one on :restart

If another existing one is stored in vifminfo file.  This allows:

    set vifminfo+=cs
    " colorscheme name

And changing color schemes in running instance, which is especially
handy for testing TUI.