Adding a new class called BreakpointManager so we don't clutter up AppDelegate

Adding a new class called BreakpointManager so we don't clutter up AppDelegate

* Source/AppDelegate.m/h: Removing the breakpoint code
* Source/BSLineNumberView.m:
([BSLineNumberView mouseDown:]): We need to add the lineNumberRange so we get an accurate number
* Source/DebuggerWindowController.m: Switching to BreakpointManager instead of AppDelegate for managing breakpoints
* Source/BreakpointManager.m/h: New files
* MacGDBp.xcodeproj: Project updates for BreakpointManager