feat(filters): percentage filter implementation

This commit adds in a simply percentage filter for adding percent (%)
signs to numbers.  If the input is not a number, the percent filter does
not do anything

client/src/js/filters/percentage.js

@@ -0,0 +1,24 @@
+angular.module('bhima.filters')
+.filter('percentage', PercentageFilter);
+
+/**
+ * Percentage Filter
+ *
+ * The percentage filter accepts a number and returns it as a percentage.
+ */
+function PercentageFilter() {
+  return function percentage(number) {
+
+    // escape if no input was passed in
+    if (angular.isUndefined(number)) { return ''; }
+
+    // cast value as number (or NaN)
+    var value = Number(number);
+
+    // angular's isNumber() method reports NaNs as numbers
+    if (!angular.isNumber(value) || isNaN(value)) { return number; }
+
+    // return the value + a percentage sign
+    return value + '%';
+  };
+}

client/src/partials/billing_services/list/list.js

@@ -30,8 +30,8 @@ function BillingServicesListController($translate, BillingServices, Accounts) {
       { field : 'account', displayName : $translate.instant('COLUMNS.ACCOUNT'), width: '*' },
       { field : 'label', displayName : $translate.instant('COLUMNS.LABEL') },
       { field : 'description', displayName: $translate.instant('COLUMNS.DESCRIPTION') },
-      { field : 'value', displayName : $translate.instant('COLUMNS.VALUE') },
-      { field : 'created_at', displayName : $translate.instant('COLUMNS.DATE'), cellFilter:'date' },
+      { field : 'value', displayName : $translate.instant('COLUMNS.VALUE'), cellFilter:'percentage', cellClass: 'text-right' },
+      { field : 'created_at', displayName : $translate.instant('COLUMNS.DATE'), cellFilter:'date', cellClass: 'text-center' },
       { field : 'edit', displayName: '', cellTemplate : editTemplate, width: 45 },
       { field : 'delete', displayName : '', cellTemplate: deleteTemplate, width: 45 }
     ]