Added support for single quotes in css.

demo/app/font-awesome.css

@@ -1,8 +1,8 @@
 .fa-glass:before {
-  content: "\f000";
+  content: '\f000';
 }
 .fa-music:before {
-  content: "\f001";
+  content: '\f001';
 }
 .fa-search:before {
   content: "\f002";

src/lib.ts

@@ -24,7 +24,7 @@ export const mapCss = (data: any, debug?: boolean): object => {
 };
 
 export const cleanValue = (val: string): string | void => {
-  const matches = val.match(/content\s*:\s*"\\f([^"]+)"/i);
+  const matches = val.match(/content\s*:\s*["|']\\f([^"|^']+)["|']/i)
   if (matches) {
     return `\\uf${matches[1]}`;
   }

src/test/cleanvalue.spec.ts

@@ -39,4 +39,11 @@ describe('Test cleanValue function', () => {
     );
   });
 
+  it('with single quotes', () => {
+    assert.strictEqual(
+      lib.cleanValue("content: '\\f000'; "),
+      '\\uf000',
+    );
+  });
+
 });

src/test/font-awesome.css

@@ -11,4 +11,4 @@
 }
 .fa-gear:before, .fa-cog:before{ content:"\f013"; }
 .fa-rotate-right:before,.fa-repeat:before{content:"\f01e"}
-.fa-dedent:before,.fa-outdent:before{content:"\f03b"}.fa-photo:before,.fa-image:before,.fa-picture-o:before{content:"\f03e"}
+.fa-dedent:before,.fa-outdent:before{content:'\f03b'}.fa-photo:before,.fa-image:before,.fa-picture-o:before{content:'\f03e'}