move sources to src/; add Moc builder

Rsconsfile

@@ -1,5 +1,19 @@
+class Moc < Rscons::Builder
+  def run(target, sources, cache, env, vars)
+    command = %W[moc -o #{target} #{sources.first}]
+    standard_build("Moc #{target}", target, command, sources, env, cache)
+  end
+end
+
 Rscons::Environment.new do |env|
-  sources = Dir["**/*.cc"]
+  env.add_builder(Moc.new)
+  sources = Dir["src/*.cc"]
+  env.build_dir("src", "build")
+  Dir["src/**/*.h"].each do |h_file|
+    moc_fname = env.get_build_fname(h_file, "_moc.cc")
+    env.Moc(moc_fname, h_file)
+    sources << moc_fname
+  end
   env.parse_flags!("!pkg-config --cflags --libs Qt5Core Qt5Gui Qt5Widgets")
   env.parse_flags!("-fPIE")
   env.Program("app", sources)