Improve warning if fusion is not installed or in non standard location

For the moment I don't see a good reason to not installating fusion
in the standard location.  If check in Docker Machine code they don't
support it. And with their large user base we can think it's safe.

Fix #435

gns3server/modules/vmware/__init__.py

@@ -35,10 +35,10 @@ from pkg_resources import parse_version
 
 log = logging.getLogger(__name__)
 
-from ..base_manager import BaseManager
-from .vmware_vm import VMwareVM
-from .vmware_error import VMwareError
-from .nio_vmnet import NIOVMNET
+from gns3server.modules.base_manager import BaseManager
+from gns3server.modules.vmware.vmware_vm import VMwareVM
+from gns3server.modules.vmware.vmware_error import VMwareError
+from gns3server.modules.vmware.nio_vmnet import NIOVMNET
 
 
 class VMware(BaseManager):
@@ -162,8 +162,8 @@ class VMware(BaseManager):
         else:
             if sys.platform.startswith("darwin"):
                 if not os.path.isdir("/Applications/VMware Fusion.app"):
-                    raise VMwareError("VMware Fusion is not installed")
-                return  # FIXME: no version checking on Mac OS X
+                    raise VMwareError("VMware Fusion is not installed in the standard location /Applications/VMware Fusion.app")
+                return  # FIXME: no version checking on Mac OS X but we support all versions of fusion
 
             vmware_path = VMware._get_linux_vmware_binary()
             if vmware_path is None:
@@ -646,3 +646,10 @@ class VMware(BaseManager):
         if path is None:
             path = shutil.which("vmplayer")
         return path
+
+
+if __name__ == '__main__':
+    loop = asyncio.get_event_loop()
+    vmware = VMware.instance()
+    print("=> Check version")
+    loop.run_until_complete(asyncio.async(vmware.check_vmware_version()))