Imported Grammar Files

 In order to have the ANTLR plugin automatically locate and use grammars used
 as imports in your main <<<.g>>> files, you need to place the imported grammar
 files in the imports directory beneath the root directory of your grammar
 files (which is <<<src/main/antlr3>>> by default of course).

 For a default layout, place your import grammars in the directory: <<<src/main/antlr3/imports>>>