Add/minus time element

[Wright55]

I have just implemented your code and it works well, but have an issue with the lights currently coming on too early. With the lighter summer nights light are coming on too early. I have many lights using presence detection based on the suns elevation. During tests lights are on before they need to be, I can see that with the darker nights later in the year they will all br later than required. Any chance of an option to add/reduce a set number of minutes as an option