Make runMethod calls public, add some comments

Sources/HummingbirdMustache/Context.swift

@@ -1,4 +1,5 @@
 
+/// Context that current object is being rendered in. Only really relevant when rendering a sequence
 struct HBMustacheContext: HBMustacheMethods {
     var first: Bool
     var last: Bool
@@ -10,6 +11,17 @@ struct HBMustacheContext: HBMustacheMethods {
         self.index = 0
     }
 
+    /// Apply method to `HBMustacheContext`. These are available when processing elements
+    /// of a sequence.
+    ///
+    /// Format your mustache as follows to accept them. They look like a function without any arguments
+    /// ```
+    /// {{#sequence}}{{index()}}{{/sequence}}
+    /// ```
+    ///
+    /// Methods available are `first`, `last`, and `index`
+    /// - Parameter name: Method name
+    /// - Returns: Result
     func runMethod(_ name: String) -> Any? {
         switch name {
         case "first":
@@ -18,10 +30,6 @@ struct HBMustacheContext: HBMustacheMethods {
             return self.last
         case "index":
             return self.index
-        case "even":
-            return (self.index & 1) == 0
-        case "odd":
-            return (self.index & 1) == 1
         default:
             return nil
         }