added a twig extension class for assets + reorganized assets structure + added command line for stylus in README

assets/css/common.css

@@ -0,0 +1,27 @@
+.clearfix:after {
+  content: ".";
+  display: block;
+  height: 0;
+  clear: both;
+  visibility: hidden;
+  overflow: hidden;
+}
+.clearfix {
+  display: inline-table;
+}
+* html .clearfix {
+  height: 1%;
+}
+.clearfix {
+  display: block;
+}
+.mailpoet_notice {
+  position: relative;
+}
+.mailpoet_notice_close {
+  position: absolute;
+  right: 0.5em;
+  top: 0.5em;
+  color: #999;
+  text-decoration: none;
+}

assets/css/mailpoet_notice.css

@@ -1,10 +0,0 @@
-.mailpoet_notice {
-    position: relative;
-}
-.mailpoet_notice_close {
-    position: absolute;
-    right: 0.5em;
-    top: 0.5em;
-    color: #999;
-    text-decoration: none;
-}

assets/css/src/common.styl

@@ -17,3 +17,14 @@
   display: block
 
 // colors
+
+// notices
+.mailpoet_notice
+    position: relative
+
+.mailpoet_notice_close
+    position: absolute
+    right: 0.5em
+    top: 0.5em
+    color: #999
+    text-decoration: none

assets/css/src/settings.styl

@@ -1,6 +0,0 @@
-body-color = invert(#333)
-body-background = invert(#ccc)
-
-body
-  color body-color
-  background-color: body-background