Support probe concretes of interface or abstract class

[zhongl]

All interface and abstract class can be used to tracing it's concrete.

Unlike tracing normal class, the method filter you input supposed to be (interface or abstract class)simple name with a plus, like InterfaceSimpleName+.

In method filter auto-completion list, all the interfaces and abstract classes will show the simple name with a plus at the end, like this:

housemd> trace TraceTarget
TraceTarget      TraceTarget$A    TraceTarget$B    TraceTarget$C+   TraceTarget$CL   TraceTarget$D+ 

[coderplay]

That's really cool !