Added Humidex

The Humidity Index, or Humidex, is a measure that can indicate fatigue whilst performing activities. It should be used as a comparative measure on an individualized level.
Added Humidex Import

Humidex needs to be imported to Plot.py to work
Humidex, Dewpoint not nessesary
Fixed Humidex Offset

Apparently Phthon didn't like my liberal use of spaces
LiveLog.py Compatibility Fix

Python may behave unexpectedly when there are extra spaces around calculations, this function is now compatible by removing spaces from fHumidex
Added Humidex Guide

Probably a bit long winded, cut things out if desired
Humidex, Useage Guide

This is some kind of draft that waffles on a bit. I think it could be an interesting read to the right person
Humidex Graph Template

Humidex graph template added to example_graph_template folder
Merge pull request #2 from aesce/master

Added Humidex function to 'conversions.py'.