This is an old PR so had some problems after merging in master.

- Fix for min and max that were not getting passed into the
applyLogScale function
- Fix for when min/max were undefined rather than null
- Fix for decimal ticks, as this PR populates the ticks itself then
it also needs to calculate the number of decimal places too. Flot
was showing the wrong number of decimal places sometimes otherwise
on the y-axis.