Monthly Adjust per Station

[cdesouza]

Thank you for your help, thank you for the enhancements/bug fixes and thank you for merging my code. I hope that the plugin will prove useful to more people than just me.

A couple of ideas for the future:

• a version scheme for the plugins
  
• a standard style guide for the plugins
  
• a readonly version of the variable gv.rs that contains the original schedule information before it was changed by any plugins may be useful if several plugins try to change the schedule.
  

But for now, back to my moisture sensor plugins.