lui: clean up breakpoint window, and allow multi-line list items

* Clean the SBBreakpoint: id = out of the output
* clamp output to window width (eventually we should be able to scroll
left/right)
* On 'tab', expand a breakpoint to show its locations
* Allow enter/space to toggle breakpoints


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@192766 91177308-0d34-0410-b5e6-96231b3b80d8