Change folder structure: don't have a java folder for 1 class
Remove mainClassName_ from DebugConnector
It is not needed. The JavaDebugger now just waits for the VM start event
and then registers the needed Classes where we need to break.

handleVMStart and handleClassPrepare are now the same methods, but we
cannot assume that stays this way thus they are separate. As one might
want to query Event information which is different depending on the
Event.
Remove classIdMap_
It is not really needed, and it wasn't used correctly anyway (no
clearing between program runs)
Rename: sendBreakpoint -> setBreakpoint
Remove mehodInfos_ caching
It was incorrectly used anyway (never cleared)
Rename: currentBreakpointKey_ -> currentBreakpointItem_
Remove some unusde code