Commit Briefs
schedule ui redraw on tab new/free
this helps to correctly manage the tab bar when tab-bar-show is 1.
add tab-bar-show option to control the tab bar rendering
If tab-bar-show is -1 hide the tab bar permanently, if it's 0 show it unconditionally. If it's 1, show the bar only when there is more than one tab.
simplify ncurses window setup
Don't bother computing the correct initial sizes for the windows, just call rearrange_windows before the event loop.