Renamed Theme/Axis properties

showGridlines  => shouldShowGridlines
showPoints     => shouldShowPoints
axisLabelFont  => axisTitleFont
axisLabelColor => axisTitleColor
Updated change log
Removed duplication of IE11 highlight fix in change log
Axis.label => axis.title
Renamed parameter: axisLabel => axisTitle
Renamed Axis.label => title
Renamed test variables

expectedAxisLabelHeight => expectedAxisTitleHeight
expectedAxisLabelWidth => expectedAxisTitleWidth
Merge branch 'develop' of https://github.com/ScottLogic/insight into rename-theme-props

Conflicts:
	Changelog.txt
Merge pull request #230 from niksoper/rename-theme-props

Renamed Theme/Axis properties