Added Mustache adapter

spec/fixtures/test.mustache

@@ -0,0 +1 @@
+<span>{{pid}}</span>

spec/mustache_spec.cr

@@ -0,0 +1,26 @@
+require "./spec_helper"
+require "../src/mustache"
+
+class MustacheView
+  def has_key?(name)
+    name == "pid"
+  end
+
+  def [](name)
+    name == "pid" ? Process.pid : nil
+  end
+
+  Kilt.file "spec/fixtures/test.mustache", "__kilt_io__", self
+end
+
+describe Kilt do
+
+  it "renders ecr" do
+    Kilt.render("spec/fixtures/test.mustache", { "pid" => Process.pid }).should eq("<span>#{Process.pid}</span>")
+  end
+
+  it "works with classes" do
+    MustacheView.new.to_s.should eq("<span>#{Process.pid}</span>")
+  end
+
+end