Accept "source" as an alternative to "recipe"

src/bin/installer.rs

@@ -68,7 +68,7 @@ fn main() {
         // List the packages that should be fetched or built by the cookbook
         for (packagename, package) in &config.packages {
             match package {
-                PackageConfig::Build(rule) if rule == "recipe" => {
+                PackageConfig::Build(rule) if rule == "recipe" || rule == "source" => {
                     println!("{}", packagename);
                 }
                 PackageConfig::Build(rule) if rule == "binary" => {

src/bin/list_packages.rs

@@ -55,7 +55,7 @@ fn main() {
     // List the packages that should be fetched or built by the cookbook
     for (packagename, package) in &config.packages {
         match package {
-            PackageConfig::Build(rule) if rule == "recipe" => {
+            PackageConfig::Build(rule) if rule == "recipe" || rule == "source" => {
                 println!("{}", packagename);
             }
             PackageConfig::Build(rule) if rule == "binary" => {