Pluralize common variant unit names

This adds the most popular unit names as singular and plural to our
locale for translation. The added Javascript performs a reverse lookup
to find the right singular/plural form of a unit name in that language.

spec/javascripts/unit/admin/products/services/option_value_namer_spec.js.coffee

@@ -0,0 +1,26 @@
+describe "OptionValueNamer", ->
+  subject = null
+
+  beforeEach ->
+    module('admin.products')
+    inject (_OptionValueNamer_) ->
+      subject = new _OptionValueNamer_
+
+  describe "pluralize a variant unit name", ->
+    it "returns the same word if no plural is known", ->
+      expect(subject.pluralize("foo", 2)).toEqual "foo"
+
+    it "returns the same word if we omit the quantity", ->
+      expect(subject.pluralize("loaf")).toEqual "loaf"
+
+    it "finds the plural of a word", ->
+      expect(subject.pluralize("loaf", 2)).toEqual "loaves"
+
+    it "finds the singular of a word", ->
+      expect(subject.pluralize("loaves", 1)).toEqual "loaf"
+
+    it "finds the zero form of a word", ->
+      expect(subject.pluralize("loaf", 0)).toEqual "loaves"
+
+    it "ignores upper case", ->
+      expect(subject.pluralize("Loaf", 2)).toEqual "loaves"