Fix Windows registry editing argument quoting

When we want a literal double-quote symbol within the registry value,
we need to escape it with backslash. In the Java source, we need to
escape backslash and quote symbols when within a string literal, so:

    In Java code: "\\\"something.exe\\\"
    registry value -> "something.exe"

Author: ctrueden

src/main/java/org/scijava/desktop/platform/windows/WindowsSchemeInstaller.java

@@ -100,7 +100,7 @@ public void install(final String scheme, final String executablePath) throws IOE
 			{"reg", "add", keyPath, "/v", "URL Protocol", "/f"},
 			{"reg", "add", shellPath, "/f"},
 			{"reg", "add", openPath, "/f"},
-			{"reg", "add", commandPath, "/ve", "/d", "\"" + executablePath + "\" \"%1\"", "/f"}
+			{"reg", "add", commandPath, "/ve", "/d", "\\\"" + executablePath + "\\\" \\\"%1\\\"", "/f"}
 		};
 
 		// Execute commands