Update sensnodetx.ino

1) Add declaration for variables because of ISO error in loop, DHT_SENSOR float h; // define humidity DTH variable float t; //define temperature DTH variable.
2) Change for BMP085/BMP180 and SHT21 declaration test not working properly, //#ifdef SHT21_SENSOR || BMP_SENSOR 
3) Add BAND variable in rf12_initialize(NODEID, BAND , NETWORK);, BAND declared in configuration.h - define BAND RF12_433MHZ
4) Reduce space by existence of test  declaration #ifdef DS18B20 int ds_array[DS_COUNT] ...