Added THN132N support

Hi, 

added some code to distinguished THR228N from THN132N (as it seems they both share 0xEC40 sensor code). I tested the code with THN132N sensor and it works. 

Regards,
Andrea

// quote test
$ ./src/rtl_433
Registering protocol[01] Rubicson Temperature Sensor
Registering protocol[02] Prologue Temperature Sensor
Registering protocol[03] Silvercrest Remote Control
Registering protocol[04] ELV EM 1000
Registering protocol[05] ELV WS 2000
Registering protocol[06] Waveman Switch Transmitter
Registering protocol[07] Steffen Switch Transmitter
Registering protocol[08] Oregon Scientific Weather Sensor
Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Found Rafael Micro R820T tuner
Exact sample rate is: 250000.000414 Hz
Sample rate set to 250000.
Sample rate decimation set to 0. 250000->250000
Bit detection level set to 10000.
Tuner gain set to Auto.
Reading samples in async mode...
Tuned to 433920000 Hz.
Thermo Sensor THN132N Channel 1, Temp: 26.7C  80.1F
Thermo Sensor THN132N Channel 1, Temp: 26.7C  80.1F
Thermo Sensor THN132N Channel 1, Temp: 26.6C  79.9F
Thermo Sensor THN132N Channel 1, Temp: 26.6C  79.9F
Thermo Sensor THN132N Channel 1, Temp: 26.5C  79.7F
Thermo Sensor THN132N Channel 1, Temp: 26.5C  79.7F
Thermo Sensor THN132N Channel 1, Temp: 26.4C  79.5F
Thermo Sensor THN132N Channel 1, Temp: 26.4C  79.5F
...
// end quote test