Adjustments for creating installations on various operating systems

Add code signing options for macOS.
Adjust make.bat to create venv to use PyInstaller.
Preparing script for Linux to use in /usr/bin.

data/revpicommander

@@ -1,3 +1,9 @@
 #!/bin/sh
+# Used to call the entry point, if packed with pybuild as application.
+# PYBUILD_INSTALL_ARGS=--install-lib=/usr/share/revpicommander/ \
+#                      --install-scripts=/usr/share/revpicommander/
+#
+# In that case the entry point will not find the revpicommander module in
+# the python lib.
 
-exec "/usr/share/revpicommander/revpicommander.py" "$@"
+exec "/usr/share/revpicommander/revpicommander-gui" "$@"

data/revpicommander.desktop

@@ -1,5 +1,5 @@
 [Desktop Entry]
-Name=RevPi PLC Commander
+Name=RevPi Commander
 Comment=Controls the Python PLC program on your Revolution PI
 Comment[de]=Kontrolliert das Python PLC Programm auf dem Revolution PI
 Exec=/usr/bin/revpicommander
@@ -7,4 +7,3 @@ Icon=revpicommander
 Terminal=false
 Type=Application
 Categories=Application;
-#StartupNotify=true