Reads the raw (uncompensated) pressure level from the sensor.

def read_raw_pressure(self):
        """Reads the raw (uncompensated) pressure level from the sensor."""
        self.i2c.write8(BMP085_CONTROL, BMP085_READPRESSURECMD + (self._mode << 6))
        if self._mode == BMP085_ULTRALOWPOWER:
            time.sleep(0.005)
        elif self._mode == BMP085_HIGHRES:
            time.sleep(0.014)
        elif self._mode == BMP085_ULTRAHIGHRES:
            time.sleep(0.026)
        else:
            time.sleep(0.008)
        msb = self.i2c.read_U8(BMP085_PRESSUREDATA)
        lsb = self.i2c.read_U8(BMP085_PRESSUREDATA+1)
        xlsb = self.i2c.read_U8(BMP085_PRESSUREDATA+2)
        raw = ((msb << 16) + (lsb << 8) + xlsb) >> (8 - self._mode)
        self.logger.debug('Raw pressure 0x{0:04X} ({1})', raw & 0xFFFF, raw)
        return raw