Added mixins lifted from FA, added rotations based on FA and existing functionality.

scss/_mixins.scss

@@ -0,0 +1,46 @@
+// mixins lifted directly from FontAwesome
+// -------------------------
+
+@mixin wi-icon() {
+
+  display: inline-block;
+  font: normal normal normal #{$wi-font-size-base} / 1 WeatherIcons; // shortening font declaration
+  font-size: inherit; // can't have font-size inherit on line above, so need to override
+  text-rendering: auto; // optimizelegibility throws things off #1094
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  transform: translate(0, 0); // ensures no half-pixel rendering in firefox
+
+}
+
+@for $i from 0 through 270 {
+
+  @if $i == 0 or $i % 45 == 0 {
+
+    .#{$wi-css-prefix}-rotate-#{$i} {
+
+      wi-icon-rotate(#{$i})
+    }
+  }
+}
+
+@mixin wi-icon-rotate($degrees) {
+
+  @if $degrees == 0 or $degrees % 90 == 0 {
+
+    $rotation: $degrees / 90;
+    filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=#{$rotation});
+  }
+
+  -webkit-transform: rotate(#{$degrees}deg);
+      -ms-transform: rotate(#{$degrees}deg);
+          transform: rotate(#{$degrees}deg);
+}
+
+@mixin wi-icon-flip($horiz, $vert, $rotation) {
+
+  filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=#{$rotation});
+  -webkit-transform: scale($horiz, $vert);
+      -ms-transform: scale($horiz, $vert);
+          transform: scale($horiz, $vert);
+}

scss/_rotated-flipped.scss

@@ -0,0 +1,48 @@
+// rotated and flipped icons
+// -------------------------
+
+$rotations-requiring-ie-fix: (
+
+  "flip-horizontal",
+  "flip-vertical"
+);
+$z: '';
+
+@for $i from 0 through 359 {
+
+  @if $i == 0 or $i % $wi-rotate-by  == 0 {
+
+    $Z: #{$wi-css-prefix}-rotate-#{$i};
+
+    .#{$z} {
+
+      @include wi-icon-rotate($i);
+    }
+
+    // check if this item needs
+    @if $i == 0 or $i % 90 == 0 {
+
+      $rotations-requiring-ie-fix: append($rotations-requiring-ie-fix, #{$z});
+    }
+  }
+}
+
+.#{$wi-css-prefix}-flip-horizontal { @include wi-icon-flip(-1, 1, 0); }
+.#{$wi-css-prefix}-flip-vertical   { @include wi-icon-flip(1, -1, 2); }
+
+// ie 8-9 fix
+// -------------------------
+
+// todo: check on assigning an array of selectors to the selector instead of this
+//       unnecessary duplication of code
+
+:root  {
+
+  @each $fix in $rotations-requiring-ie-fix {
+
+    &.#{$fix} {
+
+      filter: none;
+    }
+  }
+}

scss/_variables.scss

@@ -4,6 +4,7 @@
 $wi-font-path     : "../fonts" !default;
 $wi-font-size-base: 14px !default;
 $wi-css-prefix    : wi !default;
+$wi-rotate-by     : 45 !default;
 $wi-version       : "1.3.0" !default;
 // $wi-border-color:     #eee !default;
 // $wi-inverse:          #fff !default;