Major Description
While PropertiesConfiguration is tolerant of several different key/value separator characters when reading a properties stream, it is hard-wired to use an "=" character when writing them out again.
Can we please have a way to customise this? Seems like a perfect use for the PropertiesConfigurationLayout.
Sadly, because of the way that PropertiesWriter has been implemented, it's impossible to extend and override this behaviour without copying large chunks of code.