Some fixes to pluginbase.
Some fixes to pluginbase.

simudream/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,Elizaveta239/PyDev.Debugger,fabioz/PyDev.Debugger,simudream/PyDev.Debugger,Elizaveta239/PyDev.Debugger,Elizaveta239/PyDev.Debugger,fabioz/PyDev.Debugger,fabioz/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,simudream/PyDev.Debugger,fabioz/PyDev.Debugger,Elizaveta239/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,simudream/PyDev.Debugger,fabioz/PyDev.Debugger,Elizaveta239/PyDev.Debugger