CSS3: Add turn unit to <angle> definition

Definition https://developer.mozilla.org/en-US/docs/Web/CSS/angle
Fixes #216
Fixes CSSLint/csslint#662

Author: nschonni

src/css/PropertyValuePart.js

@@ -68,6 +68,7 @@ function PropertyValuePart(text, line, col, optionalHint) {
             case "deg":
             case "rad":
             case "grad":
+            case "turn":
                 this.type = "angle";
                 break;
 

src/css/TokenStream.js

@@ -661,7 +661,7 @@ TokenStream.prototype = mix(new TokenStreamBase(), {
 
             if (/^em$|^ex$|^px$|^gd$|^rem$|^vw$|^vh$|^vmax$|^vmin$|^ch$|^cm$|^mm$|^in$|^pt$|^pc$/i.test(ident)) {
                 tt = Tokens.LENGTH;
-            } else if (/^deg|^rad$|^grad$/i.test(ident)) {
+            } else if (/^deg|^rad$|^grad$|^turn$/i.test(ident)) {
                 tt = Tokens.ANGLE;
             } else if (/^ms$|^s$/i.test(ident)) {
                 tt = Tokens.TIME;
@@ -1045,4 +1045,3 @@ TokenStream.prototype = mix(new TokenStreamBase(), {
 
     }
 });
-

tests/css/TokenStream.js

@@ -358,6 +358,10 @@ var YUITest = require("yuitest"),
             "50.0GRAD"   : [CSSTokens.ANGLE],
             ".5Grad"     : [CSSTokens.ANGLE],
 
+            "5turn"      : [CSSTokens.ANGLE],
+            "50.0TURN"   : [CSSTokens.ANGLE],
+            ".5turn"     : [CSSTokens.ANGLE],
+
             "5ms"           : [CSSTokens.TIME],
             "50.0MS"        : [CSSTokens.TIME],
             ".5Ms"          : [CSSTokens.TIME],