compatibilty with forecast.io api icon names

For #55

weather-icons/icon-classes.less

@@ -178,6 +178,13 @@
 .@{weather-icons-prefix}-beafort-11:before                     { content: @beafort-11           ; }
 .@{weather-icons-prefix}-beafort-12:before                     { content: @beafort-12           ; }
 
+// Alias classnames for Forecast.io API
+.@{weather-icons-prefix}-clear-day:before                      { content: @day-sunny                   ; }
+.@{weather-icons-prefix}-clear-night:before                    { content: @night-clear                 ; }
+.@{weather-icons-prefix}-wind:before                           { content: @windy                       ; }
+.@{weather-icons-prefix}-partly-cloudy-day:before              { content: @day-cloudy                  ; }
+.@{weather-icons-prefix}-partly-cloudy-night:before            { content: @night-partly-cloudy         ; }
+
 // Wind Variables 1.3
 .@{weather-icons-prefix}-wind-default:before                   { content: @wind-default         ; }
 .wind-rotate(@degrees) {
@@ -244,4 +251,4 @@
 .@{weather-icons-prefix}-moon-waning-crescent-3:before      { content: @moon-waning-crescent-3      ; }
 .@{weather-icons-prefix}-moon-waning-crescent-4:before      { content: @moon-waning-crescent-4      ; }
 .@{weather-icons-prefix}-moon-waning-crescent-5:before      { content: @moon-waning-crescent-5      ; }
-.@{weather-icons-prefix}-moon-waning-crescent-6:before      { content: @moon-waning-crescent-6      ; }
+.@{weather-icons-prefix}-moon-waning-crescent-6:before      { content: @moon-waning-crescent-6      ; }