Second trial for #279 This time I keep pivateLibraryPath and PrivateLibrary path in sync. This because the reference doesn't seem to work on windows

Author: jantje

it.baeyens.arduino.core/src/it/baeyens/arduino/tools/ArduinoHelpers.java

@@ -370,7 +370,7 @@ public static void setProjectPathVariables(IProject project, IPath platformPath)
 	    pathMan.setURIValue(ArduinoConst.WORKSPACE_PATH_VARIABLE_NAME_HARDWARE_LIB, URIUtil.toURI(arduinoHardwareLibraryPath));
 	    pathMan.setURIValue(ArduinoConst.PATH_VARIABLE_NAME_ARDUINO_PLATFORM, URIUtil.toURI(platformPath));
 	    pathMan.setURIValue(ArduinoConst.PATH_VARIABLE_NAME_ARDUINO_PINS, URIUtil.toURI(PinPath));
-	    pathMan.setURIValue("ArduinoPivateLibPath", URIUtil.toURI("${" + ArduinoConst.WORKSPACE_PATH_VARIABLE_NAME_PRIVATE_LIB + "}"));
+	    // pathMan.setURIValue("ArduinoPivateLibPath", URIUtil.toURI("${" + ArduinoConst.WORKSPACE_PATH_VARIABLE_NAME_PRIVATE_LIB + "}"));
 
 	} catch (CoreException e) {
 	    Common.log(new Status(IStatus.ERROR, ArduinoConst.CORE_PLUGIN_ID,

it.baeyens.arduino.core/src/it/baeyens/arduino/ui/ArduinoPreferencePage.java

@@ -227,6 +227,8 @@ private void setWorkSpacePathVariables() {
 	    pathMan.setURIValue(ArduinoConst.WORKSPACE_PATH_VARIABLE_NAME_ARDUINO_LIB,
 		    URIUtil.toURI(ArduinoIDEPath.append(ArduinoConst.LIBRARY_PATH_SUFFIX).toString()));
 	    pathMan.setURIValue(ArduinoConst.WORKSPACE_PATH_VARIABLE_NAME_PRIVATE_LIB, URIUtil.toURI(mArduinoPrivateLibPath.getStringValue()));
+	    // the line below is added because eclipse seems to keep on using the old value.
+	    pathMan.setURIValue("ArduinoPivateLibPath", URIUtil.toURI(mArduinoPrivateLibPath.getStringValue()));
 	    pathMan.setURIValue(ArduinoConst.WORKSPACE_PATH_VARIABLE_NAME_ARDUINO, URIUtil.toURI(ArduinoIDEPath));
 	} catch (CoreException e) {
 	    Common.log(new Status(IStatus.ERROR, ArduinoConst.CORE_PLUGIN_ID,