Tests and fix for upstream css-color-function bug (postcss#33)

* Writes failing tests to demo problem

* Updates failing test (just getting travis to run)

* Uses Ian's 1.3.1 tag of css-color-function

* Points to latest 1.x series of color-func

Author: tylergaw

package.json

@@ -17,7 +17,7 @@
     "index.js"
   ],
   "dependencies": {
-    "css-color-function": "^1.3.0",
+    "css-color-function": "~1.3.3",
     "postcss": "^6.0.1",
     "postcss-message-helpers": "^2.0.0",
     "postcss-value-parser": "^3.3.0"

test/fixtures/color.css

@@ -10,3 +10,9 @@ body {
 
   border-color: color(#999 a(0.8)) color(#999 a(0.8));
 }
+
+.withAlpha {
+  color: color(black a(80%) contrast(99%));
+  background-color: color(red a(50%) shade(50%));
+  border-color: color(red a(80%) tint(50%));
+}

test/fixtures/color.expected.css

@@ -10,3 +10,9 @@ body {
 
   border-color: rgba(153, 153, 153, 0.8) rgba(153, 153, 153, 0.8);
 }
+
+.withAlpha {
+  color: rgba(255, 255, 255, 0.8);
+  background-color: rgba(128, 0, 0, 0.5);
+  border-color: rgba(255, 128, 128, 0.8);
+}