Using ':' as the option delimiter breaks Windows build for some plugins

For plugins that accept options for configuration of, say file location. One would sometimes set something like
myplugin {
option "${projectDir}"/src/main/resources/mytemplate"
}

And that breaks in Windows because the plugin is forming a command with stuff like
myplugin_out=C:/myproject/src/main/resources/mytemplate:...
and that breaks because the protobuf plugin now just pass myplugin_out=C to the plugin myplugin as it parses the options expecting ":" are delimiters.

Maybe it should use a different character for delimiter, something that does not cause platform directory parth issue.