Fix clean to not remove default lua files

build.moon

@@ -77,7 +77,7 @@ class SeleneBuild
     clean_file: (path) =>
         -- Clean a .lua file. Called as a callback by the
         -- directory traversal. Returns OK on success, and cannot fail
-        if path\match("^.+%.lua$")
+        if path\match("^.+%.lua$") and not path\match("conf.lua") and not path\match("main.lua")
             os.remove(path)
             print "Removed #{path}"
 
@@ -230,4 +230,4 @@ main = (arg) ->
 
     return rv
 
-os.exit(main(arg))
+os.exit(main(arg))