Make git submodule relative

.gitmodules

 [submodule "Plugin-FileBundle"]
 	path = Plugin-FileBundle
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileBundle.git
+	url = ../../OpenFlipper-Free/Plugin-FileBundle.git
 	branch = master
 [submodule "Plugin-FileBVH"]
 	path = Plugin-FileBVH
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileBVH.git
+	url = ../../OpenFlipper-Free/Plugin-FileBVH.git
 	branch = master
 [submodule "Plugin-FileHeightFieldImage"]
 	path = Plugin-FileHeightFieldImage
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileHeightFieldImage.git
+	url = ../../OpenFlipper-Free/Plugin-FileHeightFieldImage.git
 	branch = master
 [submodule "Plugin-FileLgt"]
 	path = Plugin-FileLgt
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileLgt.git
+	url = ../../OpenFlipper-Free/Plugin-FileLgt.git
 	branch = master
 [submodule "Plugin-FileOBJ"]
 	path = Plugin-FileOBJ
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileOBJ.git
+	url = ../../OpenFlipper-Free/Plugin-FileOBJ.git
 	branch = master
 [submodule "Plugin-FileOFF"]
 	path = Plugin-FileOFF
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileOFF.git
+	url = ../../OpenFlipper-Free/Plugin-FileOFF.git
 	branch = master
 [submodule "Plugin-FileOfv"]
 	path = Plugin-FileOfv
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileOfv.git
+	url = ../../OpenFlipper-Free/Plugin-FileOfv.git
 	branch = master
 [submodule "Plugin-FileOM"]
 	path = Plugin-FileOM
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileOM.git
+	url = ../../OpenFlipper-Free/Plugin-FileOM.git
 	branch = master
 [submodule "Plugin-FileOVM"]
 	path = Plugin-FileOVM
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileOVM.git
+	url = ../../OpenFlipper-Free/Plugin-FileOVM.git
 	branch = master
 [submodule "Plugin-FilePla"]
 	path = Plugin-FilePla
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FilePla.git
+	url = ../../OpenFlipper-Free/Plugin-FilePla.git
 	branch = master
 [submodule "Plugin-FilePLY"]
 	path = Plugin-FilePLY
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FilePLY.git
+	url = ../../OpenFlipper-Free/Plugin-FilePLY.git
 	branch = master
 [submodule "Plugin-FilePolyLine"]
 	path = Plugin-FilePolyLine
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FilePolyLine.git
+	url = ../../OpenFlipper-Free/Plugin-FilePolyLine.git
 	branch = master
 [submodule "Plugin-FilePTS"]
 	path = Plugin-FilePTS
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FilePTS.git
+	url = ../../OpenFlipper-Free/Plugin-FilePTS.git
 	branch = master
 [submodule "Plugin-FileScript"]
 	path = Plugin-FileScript
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileScript.git
+	url = ../../OpenFlipper-Free/Plugin-FileScript.git
 	branch = master
 [submodule "Plugin-FileSKL"]
 	path = Plugin-FileSKL
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileSKL.git
+	url = ../../OpenFlipper-Free/Plugin-FileSKL.git
 	branch = master
 [submodule "Plugin-FileSPH"]
 	path = Plugin-FileSPH
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileSPH.git
+	url = ../../OpenFlipper-Free/Plugin-FileSPH.git
 	branch = master
 [submodule "Plugin-FileSTL"]
 	path = Plugin-FileSTL
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileSTL.git
+	url = ../../OpenFlipper-Free/Plugin-FileSTL.git
 	branch = master
 [submodule "Plugin-FileVTK"]
 	path = Plugin-FileVTK
-	url = https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/Plugin-FileVTK.git
+	url = ../../OpenFlipper-Free/Plugin-FileVTK.git
 	branch = master