Update Eclipse instruction to warn about duplicate name (#251)

Added a short detail about importing a Gradle project, coming from a noob like me.

Author: SerifSummers

wiki/start/import-and-running.md

@@ -16,7 +16,7 @@ If you have just generated the project in gdx-liftoff, you may click the option
 
 1. In **IntelliJ IDEA or Android Studio**, you can choose to open the `build.gradle` file and select "Open as Project" to get started.
 
-   In **Eclipse**, choose `File -> Import... -> Gradle -> Existing Gradle Project` (make sure that your freshly generated project is not located inside of your workspace).
+   In **Eclipse**, choose `File -> Import... -> Gradle -> Existing Gradle Project` (make sure that your freshly generated project is not located inside of your workspace AND you don't have another project in your workspace with the same name).
 
    In **NetBeans** it is `File -> Open Project`.