Move source files to where SPM expectes them to be

Sources/Stencil/Include.swift

@@ -0,0 +1,50 @@
+import PathKit
+
+class IncludeNode: NodeType {
+  let templateName: Variable
+  let includeContext: String?
+  let token: Token?
+
+  class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
+    let bits = token.components
+
+    guard bits.count == 2 || bits.count == 3 else {
+      throw TemplateSyntaxError(
+        """
+        'include' tag requires one argument, the template file to be included. \
+        A second optional argument can be used to specify the context that will \
+        be passed to the included file
+        """
+      )
+    }
+
+    return IncludeNode(templateName: Variable(bits[1]), includeContext: bits.count == 3 ? bits[2] : nil, token: token)
+  }
+
+  init(templateName: Variable, includeContext: String? = nil, token: Token) {
+    self.templateName = templateName
+    self.includeContext = includeContext
+    self.token = token
+  }
+
+  func render(_ context: Context) throws -> String {
+    guard let templateName = try self.templateName.resolve(context) as? String else {
+      throw TemplateSyntaxError("'\(self.templateName)' could not be resolved as a string")
+    }
+
+    let template = try context.environment.loadTemplate(name: templateName)
+
+    do {
+      let subContext = includeContext.flatMap { context[$0] as? [String: Any] } ?? [:]
+      return try context.push(dictionary: subContext) {
+        try template.render(context)
+      }
+    } catch {
+      if let error = error as? TemplateSyntaxError {
+        throw TemplateSyntaxError(reason: error.reason, stackTrace: error.allTokens)
+      } else {
+        throw error
+      }
+    }
+  }
+}