Added note about double-clicking the Grendel app in the Finder under MacOS X. jrg

grendel/README.build

@@ -31,7 +31,8 @@ these settings may cause Grendel to fail to run in your particular environment.
 'GRen' is registered with Apple, so please don't change that setting. If you want to use Icon
 Composer to change the application icons to something you like better than an envelope, go ahead.
 You'll find the Project Builder project and resource files in PBProj/Grendel.pbproj and 
-PBProj/Grendel.icns. Project Builder will put the build products in PBProj/build.
+PBProj/Grendel.icns. Project Builder will put the build products in PBProj/build. You can double-
+click Grendel in the Finder to launch Grendel.
  
 NOTE TO ALL USERS/DEVELOPERS:
 If you add directories, copy one of the Makefiles from a neighbouring directory to use as a