Improve drush make integration

I hate to play whack-a-mole with your drush make file but i dont think its current setup adds much/any value to people actually using drush make.

I expect the GeoPHP library to be downloaded automatically when I provision the site via drush make (alone or as part of a chained make file) and I think most people agree (it is the whole point of drush make).

The duplicate project issue has been resolved upstream in drush make (#947158: Recursive makefiles can cause conflicts).

The line that includes core is also unnecessary (you can use --no-core if you need to make it without a chain) #1159548: "No core project specified" in a makefile consisting of just a library.

Attached is a patch that should move the file back (so it actually gets executed) and remove that core download line so drupal doesnt get pulled in on a nonchained make.

Not looking to re-fight a settled issue or anything here but i think this is an improvement for all concerned.