Change the help bar look, suggestions by hjacobs.

Simplify the code that renders the menu, add the version number to
the bottom.
Use a different color for showing a host name.

People complained that white on green is not readable on most
terminals, so we just use bold white here. This lead to changing
the color that's used for highlighting to be white bold, but since
it's used only in one place no side effects are expected.