[refactor] rename main to nixview, add argparsing

main.py

@@ -1,13 +0,0 @@
-import sys
-from PyQt5.QtWidgets import QApplication
-from main_window import NixView
-import argparse
-
-def main():
-    app = QApplication(sys.argv)
-    window = NixView()
-    window.show()
-    sys.exit(app.exec_())
-
-if __name__ == "__main__":
-    main()

nixview.py

@@ -0,0 +1,19 @@
+#!/usr/bin/python3
+
+import sys
+from PyQt5.QtWidgets import QApplication
+from main_window import NixView
+import argparse
+
+def main():
+    parser = argparse.ArgumentParser(description="NixView. Viewer for NIX data files. For more on nix see https://nixio.readthedocs.io/en/master")
+    parser.add_argument("file", nargs="?", default="", type=str, help="The nix file that should be opened.")
+    args = parser.parse_args()
+    app = QApplication(sys.argv)
+    window = NixView()
+    window.open_file(args.file)
+    window.show()
+    sys.exit(app.exec_())
+
+if __name__ == "__main__":
+    main()