Library using another library
I Have found the answer (by mistake)
i have added the includes to Boiler.cpp file

#include "RF24.h"
#include "RF24Network.h"
#include "RF24Mesh.h"
#include &lt;SPI.h&gt;
.
.
.
#include "Boiler.h"

RF24 radio(7, 8);                                   // Init RF24 Radio
RF24Network network(radio);                         // Init RF24 Network
RF24Mesh mesh(radio, network);                      // Init RF24 Mesh

Boiler::Boiler(int pin ,float Rev , String Last )
{
    _pin = pin;
    dev.setDevice(_pin);                    // Set Device Output (on/off)
    turnOff();
}

void Boiler::init( char nodeID)
{
    _nodeID = nodeID;
    // Connect to the mesh and set Node ID
    mesh.setNodeID(_nodeID);
    if (_DEBUG) Serial.println(F("Connecting to the mesh..."));
    mesh.begin();

    // init LCD and print init data on LCD
    myGLCD.InitLCD(60);                         // Init LCD 55 contrast
    myGLCD.setFont(SmallFont);                  // Set small font
    myGLCD.clrScr();                            // clr screen
    myGLCD.print("Boiler Device",0,0);          //Print init Data on screen
    myGLCD.print("Rev :" , 0 , 10);
    myGLCD.printNumF(_rev,1 ,35,10,'.',1,'0');
    myGLCD.print(_last,0,40);
    myGLCD.update();                            // Update display


    turnOff();
}


and now it compiles ;-)