I changed libraries ESP8266_DHT22_humidity_sensor_REST_V1_0 to ESP8266_DHT22_humidity_sensor_REST on your link. And now this happened:
Arduino: 1.6.5 (Windows 7), Board: "Generic ESP8266 Module, 80 MHz, 40MHz, QIO, 115200, 4M (3M SPIFFS), ck, Disabled, None"
In file included from C:\Users\
\Documents\Arduino\libraries\ESP8266WiFi\src\WiFiUdp.cpp:41:0:
C:\Users\
\Documents\Arduino\libraries\ESP8266WiFi\src\include/UdpContext.h: In member function 'void UdpContext::setMulticastInterface(ip_addr_t)':
C:\Users\
\Documents\Arduino\libraries\ESP8266WiFi\src\include/UdpContext.h:109:48: error: 'udp_set_multicast_netif_addr' was not declared in this scope
udp_set_multicast_netif_addr(_pcb, addr);
^
C:\Users\
\Documents\Arduino\libraries\ESP8266WiFi\src\include/UdpContext.h: In member function 'void UdpContext::setMulticastTTL(int)':
C:\Users\
\Documents\Arduino\libraries\ESP8266WiFi\src\include/UdpContext.h:117:40: error: 'udp_set_multicast_ttl' was not declared in this scope
udp_set_multicast_ttl(_pcb, ttl);
^
Multiple libraries were found for "ESP8266WiFi.h"
Used: C:\Users\
\Documents\Arduino\libraries\ESP8266WiFi
Not used: C:\Users\
\AppData\Roaming\Arduino15\packages\esp8266\hardware\esp8266\2.3.0\libraries\ESP8266WiFi
Error compiling.