[WIP] pending breakpoint support

[Andrew Cagney]

> To address Jim's concerns about having too many libraries to try the breakpoint on, a conditional could be added for the shared library or libraries to attempt the breakpoint on.  For example,

I'd not spend much time on performance problems at this stage.  As they 
say get it working (simply and correctly) (the UI, test cases, ...); and 
then if time permits get it working fast.

Andrew