Pushed to version 0.1.8. Details in changelog. (Makefile, FontAwesome, sass)

assets/sass/lib/bourbon/functions/_is-number.scss

@@ -0,0 +1,11 @@
+@charset "UTF-8";
+
+/// Checks for a valid number.
+///
+/// @param {Number} $value
+///
+/// @require {function} contains
+
+@function is-number($value) {
+  @return contains("0" "1" "2" "3" "4" "5" "6" "7" "8" "9" 0 1 2 3 4 5 6 7 8 9, $value);
+}